I like Goomy the way it looks and don't really want to evolve it. What will it not learn if I leave it as a Goomy? Also, what's a good moveset for Goomy?
Well, the downsides are, like any other Pokemon, it won't be as strong as any of its evolved forms.
(I suck at battling so these moves might not be the best):
You will not learn these moves by leveling up: