As somebody who only has healers and PVP's I can see why ppl would think we are OP. But i really think it's just a team balance issue and a bit of what type of class you are playing. On my Op/scoundrel I melt against a good sage/sorc, the spec with all the damn dot's i think. Also i notice when i go against a premade my healing is a lot more ineffective because the damage they put out tends to be higher and more focused, to the point where I've lost teammates before i was about to get off a 2nd cast. And yes 1v1 i can be hard to kill but at other times I've gone 1v1 and just got shut down.
Maybe if there was some system in place to make sure teams were balanced in matches things would be a bit better.