Normally I'd say being able to clear content isn't a hallmark of good tank design, but all of the tanks are so close to each-other in terms of offense and utility that it honestly is irrelevant. WAR has crazy good personal cooldowns and still has the best cheese skill in Holmgang considering its hilariously short cooldown, and DRK is basically unbreakable except he can put that shield on other people if he so chooses.