I'm fine with Zap Cannon getting a buff. Anything that improves Probopass is good with me :) --- "Earth is a silly place. Half the world has no clean water. And the other half has so much, they poo in it."
I'd give it a Base Power of 200 but NOT give it to a No Guard Pokemon.
What would something like Machamp do with Zap Cannon? His SPEED is higher than-... Oh, wait... No it's not. Zap Cannon on Machamp would actually be pretty broken, come to think of it. --- I'm not easily impressed; I'm usually oblivious to whatever's in front of me.