Damage wise the tanks are all very close. With this tier being mostly physical damage, including the tank busters. Dark mind becomes a wasted button for the all of M1 and M3. And Dark missionary as well. This limits your effectiveness to only M2 and M4 which is a problem because that means 1 of the 4 tanks have 2 abilities that serve no purpose to the fight which mitigation numbers wise puts them at a disadvantage.

Ultimately it doesnt matter because you can clear the content. The real question is will we see changes in 7.1