Originally Posted by
britishbubba
From a spec mechanical pov, you'll be fine in antorus playing outlaw or sub. Sub is going to shine on a few specific bosses due to shuriken combo, but the rest of the fights is going to come down to which spec you can play correctly and have the best gear for. Outlaw won't really out pace sub on single target until you have 1) enough people in your raid to proc pantheon empowerments and 2) have a golgeneth's yourself. Even then, less than 100k difference is unlikely to matter overall.
However, if you want to just pick one spec and play it for all bosses, it's going to be sub. If you don't mind keeping two weapons and two gear sets up, sub and outlaw look to be good options for the fights this tier.
You can clear mythic playing literally any of the specs in the game. The incredibly small differences in throughput between dps specs in a class is rarely going to matter outside of specific circumstances where the mechanics of a spec shine (things like destro havoc, sub shuriken combo, shadow multi dot, etc) and taking the player that messes up the least is going to be better at mechanics is going to be more favorable than taking someone that does 1% more dps theoretically, yet dies to mechanics or kills the raid by blowing up bombs on imonar.
Assassination is going to continue to be niche until they make vendetta a buff instead of a debuff. It's just too limiting of a cooldown.
To answer your original question. Yes, according to sims outlaw will be the best on average. No, you do not have to play outlaw for raid. Sub is going to be better on most likely at least eonar, high command and portal keeper (unless you need more aoe to actually kill the adds). This of course differs depending on strats and the roll that you're fulfilling. If you're being brought to just tunnel the boss (some melee do get to do this) then just play whatever. Assassination is fine if it gets to tunnel, you just won't get the dps increase that shuriken combo gives.
I've raided everywhere from top 2,000 to top 50 and this practice is not common place. There's the odd guild that gets it in their head that these very minor differences actually matter. Guild management that actually understands that player skill is more important that spec choice would not do this. You will never be in a guild where everyone in it is of the same skill level. Those guilds do not exist.
Top 1500 as you "bet" in t20 was killing maiden, with most above that killing avatar, but not kil'jaeden. Once guilds had farmed out a lot of mythic gear from the previous bosses, the entire thing of class stacking no longer mattered. The bosses were nerfed, health pools were higher, damage was higher. My guild killed avatar with 2 rogues and with boomkins soaking the touches. A far cry from the begining of the instance where you NEEDED five rogues to soak all the touches as no one else really could.
Top 1500 is not as elitist as you think it is. Even a month into the tier, class stacking is just not important, and mid level guilds that would choose to follow your idea of how to run a guild would very quickly run themselves out of players because those players could go to any other guild at the same level and not face the same misplaced elitism.
sub 5% differences just do not matter anymore. It did in WoD when you had fights like butcher that were so tightly tuned that the last inkling of dps you could eek out really mattered, but that hasn't really happened in legion beyond the first few weeks of nighthold and ToV.