Tanks do essentially play very similarly now with the removal of tp and skills being boiled down more. I honestly think it's a struggle to point out the difference between the current tanks other than that they all have at least one somewhat unique protective skill for their group or their self-heal works in a different manner than the other's.

Basically, I think tanks are the least unique role in this game at this point. having all 4, my basic setup is an exact copy of the other with rampart, their unique strong defensive, their secondary/third weaker defensives and then the group defensive with a self heal and invulnerability ability.

I honestly feel their class design is a joke at this point for tanks at least. It's always been rather close but at least you could say they had somewhat very slightly different mitigation style.