-CAUTION, ALTHOUGH THIS IS ALL HEADCANON / STUFF I WANT TO SEE HAPPEN, THERE MAY BE SPOILERS AHEAD, DEPENDING ON WHETHER OR NOT YOU KEEP UP WITH MLP NEWS / IF YOU'VE BEEN HIDING FROM THE INTERNET RECENTLY-
I would sell a neighborhood kid to
Satan Queen Chrysalis if it meant getting a S3 finale that involves Princess Celestia and Twilight switching cutie marks*/places/destinies, with our dear little dork Twilight Sparkle ending up as the hilariously unprepared and insanely despotic winged ruler of Equestria and Celestia reverting to her former unicorn state** and taking up the mantle of Ponyville town nerd... er, I mean librarian.
*A note on the cutie marks - for some reason, it didn't feel right simply switching them, so I changed them up a bit. Celestia's is meant to still be evocative of the sun, but based on Twilight's design. Twilight's is actually an amalgam of Celestia's AND Luna's - twilight being the time between night and day, a cutie mark involving both a daytime and nighttime symbol seems to work.
**Alicorns being "leveled up" unicorns is a favorite headcanon of mine.
Of course, all would be well at the end of the day - everyone would get their cutie marks back, Celestia would be reinstated as princess and Twilight would go back to doing what she does best, namely staying as far as is
humanly equinely possible from thrones and governing responsibilities of any sort.
If this doesn't happen I am going to sacrifice a Hasbro executive to Queen Chrysalis