In a way or another, it was almost written in the sky than twilight was going to turn into an alicorne somewhere in the show, I mean seriously.
Her special talent is MAGIC, so does her element, she's the personal student of celestia, she's the main raison equestria was saved... How much time now?
And most of all she's was originaly the main character of the serie and was planned since the begining to be an alicorne in the show's sript.
For my self, I think this is going to be the begining of a new adventure, and god I feel this is going to be awesome