It'd be pretty funny if, at the last minute, Game Freak changed Sylveon's attack animation to something like the one on the left, just to freak people out when they first saw it. Anyway, really cool concept, I'd never thought of Sylveon's ribbons being claws.
That's was pretty much the whole idea. The only way I can make that thing vaguely appealing to me is by thinking of it as one of those deceptive fae-beasts that are all harmless looking at first until they got you where you want you.. and then they go full on death mode. XD
I applaud what you've done with Sylveon here, but it also creeps me the hell out. That sketch on the left is the thing of nightmares. It's all 'Cute... ribbons... DEATH'.