There are differences in how tanks generate AE threat, and therefore damage. Warriors are jealous of the DK and especially paladin persistent area-based damage, and the others are jealous of the warriors burst AE threat on incoming ads. Druids are jealous of anyone with more than one button.
So, yes, one way of handling this is to give every tank a burst AE attack like Thunderclap, a sustained AE attack like Consecrate, and a mass taunt like Challenging Shout just for good measure. Thats the kind of thing we are really reluctant to do though buying Vindictus gold because it just works against the justification for having 4 tanking classes when they all perform the same way including using the same kind of tools. Now, on the other hand no tank should be horribly gimped in any of those situations, and except for rare exceptions they really arent. Were mostly talking quality of life issues here. (One such exception: DK offtanks on Yogg had trouble picking up adds and the dps couldnt afford to wait. As long as there arent a ton of fights like this though, we dont think its a systemic flaw.)