Now, when it comes to debates such as this, I try to keep my nose out of it. But, there are a few things I know that is possible. For example, Alicorn Twilight. That is definitely coming to pass, but I don't believe it shall be permanent. What I believe is that, according to sources, "Twilight changes the destinies of all the ponies" means that she possibly just swapped places with Princess Celestia or Princess Luna by accident, and her "Writing her own magic" means that she is just trying to create a spell to reverse the effect.
Now, as for the removal of Derpy, I'm not pleased with it at all. My opinion on it is that they only took her away for a short amount of time to plan something even bigger with her. Sure, the entire debate began just because of her voice sounding too harsh and her eyes being too wall-eyed, and her name, gosh, someone got BUTTHURT over a name that means NOTHING! Let's literally try and find the word DERPY in the dictionary and see if there is an actual meaning for it. OF COURSE THERE ISN'T! It was a good thing she wasn't named Ditzy, or there would be a real problem, cause Ditzy does mean slow, retarded, and the such! But, going off topic....I believe that they are jut gonna keep Derpy under wraps for a bit, then bring her back, cause whether people like it or not, Derpy is the face of the brony community, and take that away and the entire fanbase of the series will shatter FAST.
My belief: in season 4, they are gonna go away from the Mane 6 to let Twilight work with her alicorn abilities, IF SHE IS STILL AN ALICORN IN THAT SEASON, and direct the attention to some of the famous background ponies, like Derpy and Doctor Whooves....or whatever Hasbro calls the Doctor...or perhaps deal with more stuff with the Cutie Mark Crusaders. No one can be certain that Hasbro or the Hub will do anything just from pre-released information, since this information is normally ALWAYS fake. Think positive, for the things that we may hate may be a blessing in disguise.