I agree that they're going to have to address team stacking at some point. It probably won't happen until after they've pretty well finalized most of the class/weapon stats, but it does need to happen. Other games have managed it, and while it might be tougher given the diversity of classes and their roles, even a straight balance based on points or rank or something would be better than nothing.
"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." -- Bertrand Russell (I think...)