Don't forget, the branch of Hasbro that works on the show is different than the branch that produces the toys. They've done plenty of weird things with the toys that are decidedly non-canon, such as producing a pink Celestia. An alicorn Twilight episode would be kind of interesting, but I can't see them doing it as a permanent change, mainly due to the way that the show is structured. There are a few episodes that are sequential, but the majority of them aren't, and as a result it would be somewhat strange to make such a permanent alteration to a primary character, unless they took the show in a different direction and made all of the future episodes a sequential series.
Stop being a fucktard and get it through your head that you and I have at least some common ground in that we both dont care if the character is changed and think that bronies need to stop being so butt hurt about it. abate I get the feeling that you just hate bronies in general.