Going off the top of my head I was gonna say Leafeon, because the grass type doesn't give it much sustain,
and it's attack stats aren't very remarkable, but Glaceon is a close second if not 1st for having so many 4x
weaknesses, and though it's sp. at is ok, it doesn't really give it enough edge to be a sweeper, just a revenge
killer for dragons, rock etc...(only mons it can hit for supereffective) It's probably going down the next turn.