Well, its not light and sound, so i am happy. I never liked the idea of them for some reason. I wasnt realy big on the fairy type when it first came out, but after seeing the cute little things in that type, I quickly warmed up to it I want Flabebe and that new fluff ball Swirlix
I didn't want Sound, but I could have seen Light working out. It and Dark could have been super effective against each other since neither light or dark [good or evil] exists without the other. Because of old myths saying that ghosts can't stand light I could see Light being super effective to ghost. Because Grass or plants need light to live it could be weak to grass. That's not saying I want it, that's just saying that it would have worked. Sound, on the other hand... I can't think of how that would fit in with the other types.
I read somewhere that a Japanese show put on a weird play and some people dressed up to represent the fairy type. It seemed that they were trying to convey that it was strong against ice and weak to poison. This is nothing to go by, because it's so vague, but imagine if fairy really was weak to poison (which sounds plausible). That would be good for poison since it only has one type advantage and that's against grass, which already has so many weaknesses that arming a poison move isn't necessary. I've recently wanted to try out raising a Tentacruel, and it seems more appealing if it could potentially have a new strength. And if fairy was strong against ice, then that's a total good-bye to Kyurem.
I don't know about how it being weak to Ice would work, but I can't believe I didn't think of Poison. We literally have Pokémon that represent pollution and I didn't even think of it. Like I said, Fairies are nature spirits, Poison kills life, which is nature, and it's pollution. I think it's almost guaranteed.