The problem with the bubbles is that it is now a perfect defense against 6 out of 10 classes. Even the heavy with the highest bullet output can't destroy this shield.
And just this fact makes him a game breaking class no matter how you look at it.
Now I don't want to argue about whether the new sniper is OP, but all classes have to deal with him. Quote should have less problems with him as his size makes him harder to hit than anyone else (but I admit, it's still easy). Additionally he has fast speed to close in the distance to the sniper. As you can see the existence of the sniper doesn't change the fact that quote is OP, but rather reinforces this obsaervation.
And his height isn't a great argument. I wish he was taller because then he'd be a better medibuddy.
Ok this is a small weakness, but in return he has the bubble shield which is excellent at protecting your medic.