I hope a lot gets expanded on in the first episode of Season 4.
I didn't like the fact that you have no idea why Twilight is a princess, or how any of it changes her, and her glanced over coronation was pretty dissapointing.
Not to mention a large chunk of the episode was just songs and it seemed poorly done. It didn't feeli like Twilight really accomplished anything by fixing the destinies of the Mane 6 it seemed likem she walked in told them to try their true destiny and immediately they were back to normal.
It's not even about Twilight becoming an Alicorn, that didn't bug me in the least, it was the lack of reasoning behind it, it literally came out of nowhere.