In a vacuum, MCH's burst can be easily countered too, just like anything else. The goal is to create and exploit situations where it can't be.

I don't think warrior is overpowered exactly, but it probably is too out of line with the other jobs filling the tank role in its burst damage dealing capability. Could stand to have damage toned down a bit in exchange for more utility.

DRK and NIN need buffs more than anything needs nerfing