lol, I've used it. The Titan bubble is simply not OP. If a Titan drops his defender bubble and isn't using AoL you should mutual kill him every time if you know what you are doing. Things that are OP qualify as OP when you can know what you are doing but are unable to do anything about it. If the Titan is using AoL you simply run away! Also, flame shield is significantly better than the Titan overshield because it does not require you to actually kill the person. you just melee and get an overshield. The Titan defender rewards good play, it's not OP. Simple.