Every time I see a bubble, I just laugh and smash it. But I guess its ok if everyone on the other team is dumb enough to not use their Super on it or if they don't have it, just go do something else while they cap the Control point and then go take it back once the bubble is gone. The only thing that's good about Defender IMO is the Suppressor Grenade, which is the one that takes away their abilities and blinds them.