Warrior is the best tank outside of ultimates and savage. In criterion savage and below it is king due to its self sustain and the fact that mitigation requirements are lowered the moment you go outside of savage and ultimates.

The problem is that is the majority of content it is king. I'm a DRK main but even I know the most optimal way to run your daily expert is to just get on warrior and not have to worry about the rest of the party because you can do it all yourself.