I don't know why anyone would be against Grinch Leak unless they wanted a character that has yet to be deconfirmed. It's full of characters people have wanted since at least Brawl.
I, personally, am cautious, but not ruling it out, like I've said before. But if it comes true, then Sakurai has taken an already outstanding roster and doubled its awesomeness. Even Ken, who I consider the weakest link, is an understandable inclusion, and an Echo of a character I like to play as, so no objections here, haha.