0:07:33 Why send it to the Crystal Empire? Still no sight of Shining Armor. Where the hell is he? Twilight is there, he doesn't show up, the Element of Harmony, and he doesn't show up!

Seriously, they could have done this movie RIGHT AFTER the ending of Season 3: Twilight and her friends stay at Canterlot castle, the mirror could still be there (because, as I pointed out, there is no good reason to place it at the Crystal Empire), Sunset comes out at the night of the coronation, steals the crown, and there you go. Really, the whole moving the mirror to the Crystal Empire, the whole summoning Twilight... all not really needed.

Also, more loose ends!