Confusion was already a viable defender move, for example on Kadabra. Previously it had a cooldown of 1.45s and now it's 1.6s.
"Bubblestrat" still exists i.e. defeating a gym defender before it can use it's first move - but I think that Bubble is no longer a viable defender move.
Gastly with Lick would be a good attacker into that Mr Mime. I think a Weedle with Poison Sting could work too.
Mr Mime has quite high defence though, so it might not be as easy as it looks, but I can't say for sure. Try it, if it works then great, you've got a way of getting free XP quickly. If not, nothing of value was lost.
