They need to change up the way scoring in BG is done a bit in my opinion. It's very easy for a certain player class to steal the majority of the kills. I ran in a random BG yesterday where one guy got credit for 29 kills. I'm not exaggerating, and I got credit for one kill. He even whispered me with a "lol" and suggested I play his class instead when we finished.
I don't know what the solution should be, maybe make assists worth a lot more or something.