Well Reforging was removed for a few reasons. Ghostcrawler talked about them on twitter and such back then, so you can probably dig his words up on google if you want.
One reason was the increasing amount of post-modification you had to go through whenever you got a new piece of gear. Rather than simply equipping it, you first had to gem it, enchant it, reforge it, upgrade it, transmog it, and then you could equip it! Too many steps, so Blizzard decreased the amount of post-modification that items would typically require.
Another reason was that hit and armor penetration were removed, so reforging didn’t really serve much of a purpose. It was initially introduced to help players balance the amount of hit and armor penetration they had, since those were stats that you only wanted a specific amount of. With Haste, Crit, Mastery, and Versatility, the need for reforging is minimal, since those stats are all beneficial regardless of the amount you have.
And finally there was the resurgence of ReforgeLite and Ask Mr. Robot, which indicated that players didn’t actually customize their characters themselves – they just used a tool that told them what to reforge and into what. The process became a chore.
Resilience and PvP Power was also removed for a few reasons.
Resilience itself went through a few iterations and PvP Power was first introduced with MoP.
Regardless, both stats were super complicated to understand and knowing how much of each was optimal to have was a serious exercise in math.
They created a barrier between PvE and PvP that made cross-over play difficult, because the stats were useless in PvE activities, and without them you couldn’t really do any PvP.
And finally, then especially Resilience was difficult to balance across all the classes and specs, since not everyone benefitted equally much.
I think those are sort of the main reasons. Personally I quite like lots of item-tinkering and having a myriad of stats, but I’m not sure if Blizzard will reintroduce either of the above. Maybe in different forms, who knows.
And that doesn’t do it now? Having to farm CoS trinkets, BoD bosses for azerite gear, m+ for that one bis item and then HOPE you get the bis azerite from the casino.
I’m not saying the current design is without problems. But Resilience did create a barrier between PvE and PvP and limited the ability for cross-over play. The stat was mandatory in PvP and useless in PvE. That wasn’t a good design for an item stat.
Yes it did create a barrier, and…? Pvp gear is supposed to be stronger in pvp combat, not the other way around where pve gear has every advantage possible.
You asked why Resilience was removed. I said it created a barrier to entry between PvE and PvP. You pointed out that there’s also a barrier to entry today with PvE items being powerful in PvP. And that’s true. Umm…so you recognize why barriers to entry aren’t popular, yeah?
Man there is one HUGE difference. If you want to play pvp the only barrier should be that you need pvp talents, pvp items, pvp knowedgle etc. It was 100% fine that you need to get pvp things to play pvp.
Same about pve, you need pve items for pve, not maledict.
But when you are forced to play pve to have equal chance of winning in pvp something is wrong…
There are people who NEVER touch pvp because they don’t like it - i respect it so they play pve only but there are also people who play pvp only and never touch pve. Why should they be forced to play mode they dislike?
Blizzard’s stat design has shifted toward universally-useful stats over the years. I think the shift started with Cataclysm. You might remember this: