SPOILERS
BUT YOU ALREADY KNOW WHAT IT IS IF YOU ARE ON THIS SITE.
I know about the whole Twilicorn thing. I actually don't care about that aspect. What? I said I don't care. We are making a big deal out of nothing. Twilight gets wings. Whoop-dee-doo. A couple of stories have to change their tags to "Alternate Universe" Alicorns are adulterated. WE ALREADY HAVE CADENCE. Does the existence of that awful character not adulterate them enough?
Do I have problems with it? Yes, but not because she becomes an alicorn. If you REALLY want to know, I have issues with Twilight becoming a princess. It messes with the character relations. But I have a very strong feeling this will be aborted for this reason. I've already made this speech enough on how it would affect character relations. It doesn't take more than two brain cells to figure it out. Unless Hasbro is really screwing with this, it probably won't be permanent. She'll go "Oh please. I want my friends, not the throne" in an episode (maybe even the first one) and everything would go back to normal. If not, we have bigger problems.
As for Cycle, yeah I'm adopting the AU tag when I get to the bridge that needs crossing. It doesn't yet. It actually may not NEED to. There is only one thing that conflict, because I've saved my chips for the risky stuff, and it has NOTHING to do with alitwi. And actually, that other thing may perhaps go away.