A5-7 savage can be done without using tank stance thanks to unchained and that's some of the hardest content in the game. Tanks regularly output 1000-1300 DPS even while handling mechanics. I can see how some people may be against the idea if they aren't overgeared for the fight but let me give you an example of why you may want to push for dps even in a mechanic-oriented group. A6s Blaster: Immediately after the first set of mirages, if Blaster isn't under 50% he will do two back to back tank busters which hurt even if you use a cooldown. Let's say your group plays it really safe during the dashes, ensuring nobody gets hit. Well this safe play results in blaster still being at 55% or so and you keep getting those tank busters consistently. Having both your tanks in DPS stance, using unchained, will allow you to push that extra 5% skipping those 2 tank busters and taking overall less damage. I think this is a practical example, since groups in i240 gear won't have that issue but groups doing progression will. There's no danger of the tanks losing aggro because Unchained just has make up the difference in dps between tanks and damage dealers, not eclipse the entire team's aggro generation. Tanks are still generating aggro while in dps stance, it doesn't just drop off into nothing.