Fluttershy does apparently turn into a dragon though (perfect idea for an episode, and she will be solidified even further in-fanon as Dovashy). And Trixie is all but confirmed for a reappearance, although the extent of said reappearance remains to be seen. And finally, we’ll be getting more Luna. Whether or not she is actually a useful character remains to be seen as well.
I’m gunning for some Scootalove, permanent character development for Fluttershy, and a Celestia ep. Celestia’s been around since the pilot, yet she still doesn’t have an episode. For shame.