I think they're going to end up having the difficulties of being a princess prevalent throughout the new season, possibly a Princess Cadence origin story, since neither her nor Twilight have the flowing mane thingy, I would assume that she followed a similar procedure. ALSO, if they don't have a "learning to fly" episode, I will waltz up to Hasbro and slap every writer's tender face. I don't care if she was flying at the end of The Magical Mystery Cure, flight is not something to be learned simply in a day.
SCIENCE TIME!
The body mass of Twilight would have to obviously change to accommodate her small wingspan, thus meaning that she requires extra muscle mass in her chest area and less on her legs, thus increasing the difficulty of walking, and her bones would have to become hollow or porous. The reason for this is because of the weight factor. In conclusion, THEY NEED A LEARNING TO FLY EPISODE.