Earlier today, the WoW Classic Development Team gathered to answer many highly-upvoted questions on /r/classicwow . Here is a compilation of the questions and answers, with links to each.
From AltruisWoW, Executive Producer:
A: We’re not releasing specific numbers, that will likely change dramatically. Based on the response we got from name reservations, we’re anticipating large player populations for some realms initially. This may change as players switch to lower population realms. We’ll use layers to help improve performance in the short-term if large groups of players cluster in an area. We hope to reduce the use of layering over time as people spread out in each realm.
A: We have contingency plans in place to bring up additional realms quickly if needed. We may also integrate character transfers (this ultimately became a service in original WoW.)
As you can imagine, it’s difficult for us to gauge how many people will come to play Classic and stay on to experience max-level content. Ultimately, we want to see realms with healthy stable populations so we’ll try to match demand without inadvertently creating low population realms in the process.
A: Hi starfishbg, we’ve answered these questions in more detail in other posts but I’ll try to summarize answers for you. Based on the name reservations we’ve seen, the queue time on some realms will be extremely long. We’ve opened up additional realms and we’re encouraging people to set up their characters on lower population realms for a better experience. This is a good time to coordinate with your friends/guilds to switch if they’ve reserved names on a full realm. We are considering integrating character transfer services later on, when players have higher level characters.
A: We’re considering integrating a character transfer service once players have reached higher levels. This was available in the original WoW. We’ll look at the rules we imposed at that time and also discuss the implications of players moving to a new realm. We believe realm identity is an important aspect of Classic so any guidelines around transfers should support this belief.
Q: Will there be paid services for Classic?
A: We aren’t considering other services beyond character transfer at this time.
A: Character Boosts are not in keeping with Classic. We don’t want to break any hearts.
Q: What are the plans after Phase 6? More content for classic or moving to TBC?
A: We’ve done most of the hard work by bringing back 1.12 so progressing to Burning Crusade would be a lot easier for us. Our plan is to identify everything we need to do should we ever decide to go this route. We want to be sensitive to the desires of our players. Some may want BC and some may not. We’ll be following the Classic community closely to help determine what our next steps should be.
A: There is no direct means for characters in BfA to transfer gold to characters in WoW Classic. This would be highly disruptive for Classic as the economies of these two games are very different.
Gold exchange between players in WoW is subject to our terms of service. Purchase of gold from 3rd parties could lead to suspension or banning of accounts.
A: We’re looking into what would be required to support BC and WotLK should we decide to go that route. The guiding principle for WoW Classic was staying faithful to the original game.
It’s less clear what our direction should be with BC and WotLK. As you point out, it is likely that some features of these expansions will not be universally embraced by the Classic community. We’ll be following player progression and sentiment to help guide us in our next steps.
Q: How are you gonna deal with Gold Sellers and Cheaters ?
A: WoW Classic has much better means for detection that the original WoW. All WoW players are subject to our terms of service. Violation could result in suspension or banning of accounts.
From Chromschi, Senior Game Producer:
Q: Will you offer free realm transfers if servers get way overpopulated after launch?
A: This is definitely one of the options we are considering. But for now, we are encouraging players to use the name reservation period to transfer their characters to lower population realms.
A: On the most popular servers, such as Herod and Shazzrah, we are currently estimating lengthy queue times - up to several hours or more in certain instances. That is why we strongly encourage players to use the name reservation period to transfer their characters and their guilds to lower pop realms.
Q: Will Mankrik’s wife be moved to recreate an authentic Vanilla experience?
A: nochanges
Q: What does “success” look like for Classic WoW to the dev team?
A: “Success” for us is that players enjoy the game! We hope that those who played back in the day are overcome with nostalgia, great memories, and reconnect with old friends. We hope that new players get to experience this iconic time in MMO history and experience the world with new friends.
A: When we were going through the original source code, we uncovered a few inline developer comments. It was super interesting to read them - like messages from the past. One of the most colorful comments I enjoyed was in reference to adding spells: “whatever you do, don’t get them wet”.
Q: Will we see a maintenance downtime the morning after Launch?
A: We are not currently planning a maintenance downtime for the morning after launch.
A: As /u/altruiswow said elsewhere: We have contingency plans in place to bring up additional realms quickly if needed.
We took a careful approach here. Taking various things into consideration, we wanted to hold true to our main objective of ensuring healthy realm communities in a post-Launch world. Therefore, we felt that the best approach here was to start off with fewer realms in order to gauge player interest during the name reservation period. As we have seen players congregate on certain types of realms, we have opened up new realms with communication to that effect. While we acknowledge that queues will be part of the launch experience, we encourage players to keep an eye on the forums and message boards over the next days/weeks for communications around realms with lower populations and therefore more manageable queue times.
A: The team was very, very excited. The biggest challenge we faced with this project was figuring out whether we could pull this off from a technical perspective. But once we proved that it was possible, and we stood up a reference client, there was no looking back.
From Pazorax, Lead Software Engineer:
A: We’re absolutely committed to reaching one layer per realm by Phase 2. This is why we need to have upper bounds on the number of players connected to the realm at one time, and queue players past that point. That, of course, is why we’re willing to open new servers if necessary, and we’ve even started doing that in response to the incredibly positive reception we’ve had during the name reservation period!
A: We’ve been blown away by the response to WoW Classic. The passion from the community is exactly what got us working on this in the first place, and we see new signs of your passion and excitement every day. We’re very excited to make it a reality for all of you next week!
A: For me, some of the fun of clearing a dungeon is discovering the loot as you go, but for those who want more information: the drop tables are mostly from 1.12.
There is a significant exception to that, in Phase 5, when Relics are added to drop tables. When they were originally added, in patch 1.10, they affected drop tables significantly enough that simply removing relics from the drop table until Phase 5 wouldn’t be sufficient. It would have had effects on the drop-rates of other items that we didn’t feel were acceptable or authentic. So for that specific change to item drops, we did reproduce the boss drop-tables from the previous patch (1.9). Before Phase 5, the affected bosses have the 1.9 drop tables, and once Phase 5 hits, they’ll use the 1.10 drop tables.
That change doesn’t affect MC or Onyxia very heavily, so you should expect those drops to launch in a state very similar to their final phase 6 state. Again I don’t want to give it all away, so I’ll leave a bit to exploration and discovery here. 
A: I’m so glad you asked this question.
We’ve seen some confusion about layering, both about how it helps support our launch, and how it’s supposed to behave while its active, so I’d like to both speak to it and clear up some misconceptions about it.
First, we’re absolutely committed to reducing to one layer per realm before our second content phase goes live, and the sooner we can get there, the better. The reason we can’t do that initially is that on launch day, everybody will be clustered in the starting zones, and having players so close together causes an exponential drain on server resources. In fact, the same number of players cause more server problems crammed into Northshire than they do spread across all of Elwynn Forest. We expect that even after the first couple of days, we’ll need fewer layers than we need for the initial hours of launch, and our stress tests have confirmed that expectation.
A related concern that was raised during our pre-launch test was that capital cities felt empty, but that only occurred because we left the pre-launch test running two days past its original end date, and we didn’t reduce the number of layers at all during that test. During our launch week, as the players spread out across the world, we’ll monitor activity and reduce layers as necessary, so the world continues to feel full.
Some players have suggested using sharding in low level zones to address launch demand, both because we talked about that at Blizzcon, and because it’s what they’re used to from our modern expansions. Unfortunately, while modern WoW has content designed to work with sharding, WoW Classic does not. The most obvious example of incompatible content is Rexxar’s famously long patrol path, but there are lots of other examples throughout WoW Classic. Since we want all that content to work as it was originally designed, we’ve made sure that every layer is a copy of the entire world, so you can kite Anachronos all the way to Orgrimmar, and you can ride the boat from Ratchet to Booty Bay with the same people alongside you the whole way.
Some players have asked us to use realm caps and login queues to handle the demand, and while those are tools we have at our disposal, we don’t want to rely on them exclusively, because they keep people from playing the game.
One of the most frequently reported problems during our tests was players transferring to a layer for what seemed like no reason. There were several bugs that caused this, and we’re confident we’ve fixed them. At this point, the only thing that should cause you to change layers is accepting an invite from a player on another layer. Additionally, it should always transfer the player who was invited to the layer of the player who invited them.
Nonetheless, after accepting an invite, the layer transfer doesn’t always happen immediately, because we don’t want to transfer you in the middle of combat, or before you get a chance to loot. During our pre-launch test, we saw a few reports of what seemed like random layer transfers, but when we investigated, we realized this was due to us making that transfer delay too long. The delay was so long that players could unintentionally chain one delay into another by starting combat immediately after looting. Because of those reports, we’ve fixed the transfer delay to give you enough time to loot, without being so long that you’re left wondering why you can’t join your friend. We’ll keep an eye on that, and we may decide to reduce it further.
We’ve also seen reports of people transferring suddenly at the entrances to capital cities, which was related to the transfer delays. If you’re waiting to transfer to your friend’s layer, and you enter a capital city, we ignore the delay and transfer you immediately. The long delays were making it more likely that you’d enter a capital with a transfer pending, and now that we’ve reduced the transfer delay, it will be a bit more clear that your transfer was the result of accepting a group invitation.
Regarding PvP, we saw many posts from players wondering if getting invited to a party is a good way to escape from PvP combat. I’m pleased to say there’s actually a separate, longer transfer delay following any PvP combat. We know a lot of world PvP enthusiasts are excited for WoW Classic, and we don’t want the additional layers to feel like they’re robbing you of your kills. When the time comes to withdraw from the fight, you’ll have to escape from your enemies and get to a safe place before you’re able to join your friends on another layer.
I’d also like to clarify how multiple layers work with logout. Early in our stress testing, players reported that logging out and back in would let you hop to a new layer to farm the same mineral or herb node on different layers. That was a bug, and we’ve fixed it. Your layer assignment now persists for a few minutes between logouts, long enough that by the time the game would choose a new layer for you, that node would have respawned on its own anyway.
I hope that all makes things a bit more clear.
A: We’re planning a number of fixes to improve that experience. First, we’ve already begun opening new realms and we encourage people to switch to them. We’ve also increased the size of the realm queues, so they can hold more people before disconnecting them. And we’ve improved the error message you get, so that you’ll know you’re being disconnected because the queue is full, instead of getting a generic disconnect message.
A: I’m honestly not sure we’ve looked at that specific case. Thanks for the detailed description! We’ll take a look and we’ll make sure we get it right.
A: The catch-up gear added in 1.10 won’t be available until Phase 5.
The MC tables weren’t affected very much by the 1.10 changes. Almost all of their loot was the same from 1.5 to 1.12, so the changes you see to MC throughout our content unlocks will be very minor.
A: They’re related. Imagine a drop-table that has 2 items that each has a 50% chance to drop. If you restrict it so one of those can’t drop, the other one just became a 100% chance to drop, or you have to have a 50% chance to drop nothing.
There are various items throughout the game that were added later, and which we’ve restricted to later phases, but we took a careful look at any item we decided to restrict to make sure it didn’t affect the drop-rates of other items too much. If it did, we went back and pulled an earlier version of the drop table, so it would have an appropriate loot distribution, and the biggest of these changes was in Phase 5 (from the patch 1.10 change).
That said, none of those drop-table changes occur between Phase 1 and 2. They’re all in later phases. So yes, Bindings can drop in Phase 1. Good luck getting both of them. (I’m still missing one…)
A: Yes, that’s correct. The person who issues the invite will bring the invited players to their layer. Inviting your higher-level friends to come help you fight back is certainly something people used to do, and we encourage you to do so. Enjoy the fight!
A: This does apply to 5-man dungeons as well.
We gated specific item drops when it made sense to do so, and if those removals affected the drop rates of other items in a significant way, we used the rest of the drop-rates from the previous patch to compensate.
In fact most of the changes in Phase 5 will be changes to 5-man dungeon loot tables.
From Ogronz, Senior Software Engineer
A: #nochanges
In all seriousness, one of our core pillars is to recreate the original experiences as authentically as possible. This will extend to the required resources of the AQ War Event. We realize there is nothing we can do to unwind the knowledge gained over the years. What we do have control over is ensuring that World of Warcraft Classic matches as closely as possible to the original 1.12. data.
A: We are likely to perform some kind of realm restarts or maintenance between now and launch. However, in the minutes leading up to launch, our plan is that the realms will up and available and the Enter World button will instantly light up once we’re launched.
A: The raid reset points have been restored to their original 1.12 values.
Classic operates as part of our general World of Warcraft infrastructure. Our goals are to minimize service downtime and maximize availability. In some weeks we might not need to take realms down for maintenance.
A: One of the biggest benefits of having worked on World of Warcraft continuously since the beginning is that I have a strong grasp not only of how our game and server systems worked originally, but how they changed over time. So I can’t say there was anything “incredibly” hard. The process mainly involved a constant iteration comparing Classic to our 1.12 reference, and making fixes and adjustments when we found differences.
On a side note, I did find old bits of code that I wrote as a young engineer. I fought hard to resist the urge to clean and refactor it in places it was not technically needed (because at this point it’s been production hardened for 10+ years)
A: I found old code that stood out because I wrote it in 2005! What I am most impressed by is the longevity of our code base. We don’t toss out old systems just to rebuild again from scratch. We mostly take an evolutionary approach, which is to say we improve and extend systems as far as they can. When code systems do reach an overextended point, that’s when we try and refactor out common components or pay down tech debt. On the engineering side, the technical decisions we make should be done in service of delivering great gaming experiences.
A: return false; // argh! foiled!
Q: Hello! What are some of the perks you guys had on using Legion game engine for Classic?
A: We have VASTLY improved telemetry and error reporting tools now than we had in 2006. As someone who has fielded 3am calls, I consider this a HUGE perk! An engineering only perk is we use modern compilers and debuggers which is a huge boost to productivity, scalability, security and robustness. On the client front, our engine is much more efficient at rendering images and more stable and free of crashes in general.
A: Trick or Treat! Yes, because we’re based on patch 1.12’s data, holidays will play out as day did during that patch. So we look forward to spooky treats and happy haunts this October!
A: I absolutely did! The best part about it was being able to measure personal growth as an engineer by comparing how I might solve problems now to how I solved them in the past.
From ZoidWoW, Principal Software Engineer:
A: This is not possible in Classic. All players who were in the instance when Onyxia is engaged will be locked.
A: We are not planning to bring DX12 and the multithreaded enhancements to the Classic client. The multithreaded support greatly improves performance in large scale environments like Suramar or Boralus. Classic’s world and models are much simpler. It would also increase the system requirements.
A: This is actually not related to spell batching. Traps and AoE abilities check for the presence of targets during a heartbeat update. If the target moves through them between two heartbeat updates they will not notice the target. This is how it was in the original 1.12.
Q: How does that work with the honour calculations? They were always done in downtime.
A: When restoring the honor calculation code we re-wrote it so it can work while the game is live. Realms do not need downtime for honor to update.
Q: The only thing I wanna know is, can we still pull Lord Kazzak to Stormwind?
A: Kazzak has a hard leash in 1.12. But there are other bosses in the world that do not!
A: There is a debuff priority system in vanilla and we replicated it. The issue with range on arcane missiles was fixed by 1.12 and we’ve kept that fix.
A: Hunters. They were one of the most complicated classes in vanilla and we had to do a huge amount of work in restoring them.
A: Phases will be simultaneous across all realms in a region.
Q: What are some interesting hiccups or bugs you guys hit in redeveloping vanilla?
A: There was a bug when two priests mind control each other the mind control itself would cancel out but the camera would still switch to each other. The result is both priests would be stuck watching each other move around which hilarious and very confusing.
From Aggrend, Senior Test Lead:
A: This was indeed a bug that we have fixed and you should be able to enter most lower-level dungeons with up to 10 players, as was possible in Original WoW 1.12. There are some dungeons that had specific caps by the end of Original WoW however. To be specific, all lower level dungeons available through Maraudon should have a player cap of 10, with Blackrock Depths, Scholomance, Stratholme, and Dire Maul being capped at 5 players.
As was the case in Original WoW 1.12, Blackrock Spire should also have a cap of 10 players.
A: While we understand that this was a flavorful part of Original WoW and the earlier expansions, individual players leaving multiple player corpses and skeletons throughout the game world can lead to behavior such as spelling out advertisements, hate speech, and other negative messages. As such, this will not be a part of WoW Classic.
A: As /u/pazorax mentioned earlier, we want there to be some exploration and discovery to this, so I can’t dig super deep into exact specifics around when individual quests, items, or rep items will be available. Painting in broad strokes however, Thorium Point and Jintha’alor quests should be available during phase 1. Most quests in Cenarion Hold will be available during phase 5 along with the AQ Gate opening content. The general methodology was to make quests, recipes, items, and the like available when it makes sense to do so and feels relevant to the rest of the available content.
A: World buffs are going to function exactly as they did in 1.12 which is to say that they will remain available and will not be restricted when new phases are rolled out.
Rallying Cry of the Dragonslayer will have a cooldown. You will need to wait for the current Onyxia or Nefarian head to despawn before being able to regain the buff from a new turn-in.
A: We’ve fixed several bugs with pet commands throughout the WoW Classic beta, thanks to a ton of super detailed reports from the beta and stress tests. As several posters have pointed out, we’ve resolved many of the issues with pet responsiveness already, and I can confirm that several recent bug fixes have brought Hunter and Warlock pet responsiveness well in line with their behavior in the Reference client. If any other issues pop up, we will be quick to investigate them and take action as needed.
it was great! you just know that you are in bad time and place! and you are kind of screwed… - with skele limitation (but at least lasting longer) you would need ton of players to write something bad and still reserve that spirit of fear and curiosity.