Not really. If I'm running with people I know I go out of my way to help, tanking/pulling ect, but usually I'm there for one reason. DPS and DPS alone, which is fine by me.
I haven't had any sort of problems with Unstoppable (RB). The only thing I've ever noticed with it, was if I was taking a lot of damage then went to hit RB it wouldn't activate. I usually have to do a daily then I can actually activate unstoppable.