Is not using tanking stances actually best?

[Terkhev]

If you use offensive stance in the dungeons i guarantee you, you will be called out on it or fail to complete dungeon.

On trash pulls tank stance is a reasonable thing to keep on (tho WAR and DRK can do some magic when they go ham), but using tank stance on bosses is just a waste with their damage in 4-mans. And this has nothing to do with percentiles. The team I cleared previous savage tier with was mostly gray-green parses and we still played "meta way". Tank stances are just objectively weak - including boost you are not getting from using DPS stance, tank stance lowers your total damage by 25-30% (too lazy to find and link those calculations, sry). 20% dmg reduction you get stacks multiplicatively with cooldowns, making it worth even less. On top of that, healers have less personal DPS than tanks, so even if you could boost their damage by 20% (it's way less in reality) by using tank stance at the cost of 20% (more in reality) of your damage, it'd still be a loss.

Honestly, if you've ever been called out in dungeon for not using tank stance, it's either because your team was bad and looked for excuse, or you made some mistakes that could be made up for with tank stance.

Imo the only tank that has no reason to ever drop tank stance on trash pulls is paladin - Sword Oath is single target boost, Shield Oath is "only" -15% dmg and PLD AoE is way weaker than healer's anyway. Outside of big pulls (3+ packs) or some harder trash mobs WAR gains too much DPS with Decimate spam to ignore it (mosnters die faster - you save cooldowns or can use more at once - you are actually tankier). For DRK idk tbh. BW + Quietus feels nice but I'm not sure if it's worth it.