No matter what if you are a DD and you are pulling aggro. It is your job to adapt. Team work is just that, filling in the gaps. If the tank is not as good as you are accustomed to then you should help the tank regain control, you do this by easing off on the damage.

Going ape from the start of the fight is worse than anything a bad tank can do. The idea is to let the tank get control, THEN go ape. Tank starts to lose control. You ease off. Simples.