I have a feeling she's going to turn it all down for something about love and friendship. I'd personally turn down such a high ranking role in exchange for good friends; mostly because I have the political skill of a sponge.
That may sound morally right and in truth it is, but every leader can take that for only so long; whether it's a expire term, passing down a legacy, or when they finally die, someone must take up power.
I assume she is being taught the importance of friendship because, when she takes her seat of power, it is a very cold and lonely place. It will be the memories she has of her friends that will remind her to do what is right for a world full of friendship and love.
Nice alicorn look for Twilight, with the flowing aurora borealis in her mane and tail. Her horn also looks like it's longer. I like the book-based armour that she's wearing! Something like this has to happen in the series finale!
I'm just glad that my crazy theory is shared by so many. From the moment I saw that Hasbro promo standie of Twilight as an alicorn I knew they had planned to make it her end game. All her studying and training by Celestia and soon Luna and her Black Book of night and Twilight will be complete. Sadly I also believe that when she reaches Alicorn status the show will end. But that's okay since the show is still a great story over all.
With that in mind, and the brief dialogue between Celestia and Luna, and the book Luna pulled out at the end of the Season 3 premiere, I wonder: could there be a story-arch that spans the entire series? I love the subtle hints and multiple story-archs in this show.