There are a lot of topics already made about how good or bad War Mode is and faction imbalance, etc. This is not one of them.
Assassin buff
Removed when:
- Switch continents by portal, teleport, boat, summon, any loading screen.
- Go out of zone boundaries. If you get close to Fatigue line, and leave current specific location, but don’t leave bigger continent, you lose this buff. Has to be a bug.
- Logged out
- Joined BG/Arena/any instance
Buff is not restored when you come back into BfA zones.
This is a big bummer, because you can’t for example do WPvP and queue for BGs if you don’t want to lose this buff. Logging off is OK, you left the game - you lose buffs. But simple loading screen, porting from Kul Tiras to Zandalar, going into BG/Arane/… etc - Buff needs to be reapplied when you get back into BfA zones. Only dieing and logging off should remove it.
Bug - it has to be fixed, because player is still on the same continent, why remove buff?
To get Assassin buff:
From my experience, you need to get certain amount of kills in certain amount of time. When solo it’s 10-12 kills in ~30 mins, or 15-20 kills in ~1 hour, but more kills in less time give you this buff quicker. When in group/raid, if you’re not landing killing blows, it could take ~5 more kills to get this buff.
But, this kill counter is only for Kul Tiras OR Zandalar, and just like the buff itself - if you leave continent or get close to fatigue line - it gets reset and you need to start over. It could also take more kills to get this buff if player is switching zones, like 8 kills in Nazmir and you fly to Vol’dun - it’ll take more than 4 kills to get buff, but most of the time it’s not 10-12 if you’re in that 30 mins limit.
Dieing will also reset this counter.
With an exception for reset on dieing, this should also be changed - it should count all kills in all BfA zones on both continents. And “fatigue line / outside of zone” should not reset it if player is still on Kul Tiras or Zandalar continent map.
Reset on dieing, going to non-BfA zones and entering instances should still reset it.
Bounty:
Similar to Assassin buff, removed when:
- Leave BfA zones
- Go out of zone boundaries. If you get close to Fatigue line, and leave current specific location, but don’t leave bigger continent, you lose Bounty. Has to be a bug.
- Logged out
- Joined BG/Arena/Dungeon/any instance
Going from Kul Tiras to Zandalar and vice versa does not remove Bounty. This is good, same should be for Assassin buff.
Just like with Assassin buff - Bounty should be reapplied when going back to BfA zones. And it shouldn’t be removed on Log off. Only dieing should remove it.
Right now, a lot of players abuse all of that to escape repercussions. Many players log off, port outside BfA zones, join BG/Arena/whatever instance to remove Bounty, then go to another place to kill players till they get bounty again, and repeat.
This is very annoying, and makes whole bounty system pointless, because anyone can just abuse this system and never get caught.
And a bug (it has to be) really needs to be fixed. Because when someone hunts a bounty for a long time, finaly corner them - they just swim till the Fatigue line, and poofff no bounty anymore. Very annoying.
Getting a bounty:
It’s more random than getting Assassin buff. Principle is the same - more kills in shorter amount of time. Also more killing blows when in group usually gets you bounty, but it’s not guarantied, sometimes there was only healer who got a bounty and they did no damage whatsoever.
Going from Kul Tiras to Zandalar resets counter, just as dieing, leaving BfA zones, joining instances, etc.
Also, sometimes (most of the time for me) there is a “lag” in getting a bounty. After needed amount of players is killed - no bounty, then go to another WQ, and get a bounty on entering Tortollan WQ or Boat WQ in Vol’dun or Gryphon WQ in Xibala, etc. Sometimes on changing phases - like joining a group from another server.
Not a big deal, and could be fun when you get to Turtles, see a lot of Horde, jump into WQ to escape and BAM - they are not leaving now, until you are dead 
Claiming a bounty:
To claim bounty you need to (party):
- Do damage to player with bounty. If you’re just in a party and not a healer, chances are that you won’t be able to claim it, so be fast.
- If you a healer in a party and you are healing those who do damage to bounty, you’ll be able to claim it. At least I never heard healers couldn’t claim it when in a party.
If you’re in a Raid it’s different:
- you will be able to claim it only if you did good amount of damage to player with bounty. Sometimes I did ~5% of damage and wasn’t able to claim it. Other times I did 10%+ and was able to claim it.
- you need to be among the first to deal damage to a bounty target. Sometimes I caught up to bounty when they where already fighting and getting heals for some time, I did a lot of damage but still wasn’t able to claim it.
- seems like there is a limit of how many players from a raid will be able to claim a bounty. Can’t say exact, but I never saw a situation where more that 10 ppl from a raid where able to claim same bounty.
- if you’re healer and in the same party as dps who did damage to bounty - you’ll be able to claim it. If you’re in one of the other parties in the raid - nothing certain, but most of the time all healers in the raid who were there when bounty died and did healing/damage were able to claim it, but sometimes they couldn’t.
When you claim a bounty:
- 1 per day you’ll get 35 conquest points, bags with gold and goodies, vendor trash
- on a second bounty in the same day you’ll get 100-200 honor, vendor trash, or nothing at all
- on third and beyond - vendor trash or nothing.
Suggestions to improve claiming a bounty:
- Everyone in a party and raid should be able to claim a bounty, no matter if they are doing damage, healing or anything else. Because it’s not fair when healers in a raid heal/dispell - did their job and get nothing for it. And it’s not fair when you separate your party/raid to catch that bounty and not let it escape by cutting a different FPs or opposite side of the road/way, etc, but only some of the party/raid get rewarded for it. If party/raid is hunting a bounty and if they are successful - all should be able to claim it.
- Increase time before bounty loot bag disappears by at least 3 times. So if there is a raid fight everybody would have a chance to claim it.
- Make bounty reward Conquest points every time it’s claimed. Similar to Random BGs - 1st time it’s 35 CP, and 10-15 on 2nd and all other on the same day.
PvP vendors:
War Mode needs more PvP rewards and it needs to give an ability to progress with your character.
If Conquest points made into currency, and PvP vendors are added that sell all PvP gear (not just Azerite gear) for different ilvls (similar to new M+ vendors in 8.1) - it would make WPvP a lot more appealing for all players.
And it makes sense - PvP activity gives ability to work towards PvP rewards to progress you character.
This is a shortest section of this topic, but I think it’s the most Important.
Giving % bonus for WQ is OK. Compensate players for more time needed to do WQ is OK. But in the end it’s almost meaningless and never will be good enough, no matter how high it is.
Giving players ability to progress by participating in certain activity - that would make whole experience a lot more interesting and appealing for more players, and it will make players, who don’t mind PvP but feel like War Mode in current state is a waste of time, to actually engage in it and work towards meaningful rewards and progression.