I've just resubbed after a prolonged absence, and decided to finally roll tank, something I wanted for years. Now, my question is which is the overall strongest class so far in MoP? I'm leaning towards Warrior, but I'm not quite sure.
Since Cata there is no such thing. All of the tanks are capable of performing in all content and while there are certain fights where one particular tank shines over another, in the end they're all the same.
We can't decide for you; you have to do the work yourself to make the decision.