I was a big My Little Pony fan when I was around eight. Seeing this movie as a teenager, I was disappointed. First off, I didn't like the design of the ponies. The eyes were larger than in the show and their snouts were shorter, and they seemed a little chubbier. It made them look babyish. Second, some of the Mane Six barely contributed anything to the movie, such as Fluttershy. I wish they'd written her in more. Third, we never learned what the Storm King's motivations were or really anything about him, which made for a boring and underdeveloped villain. Fourth, some of the things the Mane 6 did were completely out of character. Would Twilight Sparkle, the Princess of FRIENDSHIP, really try to steal the pearl from the seaponies behind their back instead of trying to befriend them, after seven seasons of development? I should think not. Fifth, the fight that the princesses put up at the beginning of the movie was so weak. And where was the royal guard? There's more I could say but I'll leave it at that for now.
Overall, I found this movie disappointing as a fan. It wasn't awful, but it wasn't very good either. I think they could have done a much better job with it.