>>41664
Mostly I didn't like how the writers obviously didn't plan for it, so it goes pretty much nowhere, and that it messed with her dynamic with the rest of the Mane 6. This is supported by fact that they just plopped a stylistically clashing crystal castle in Ponyville and Twilight says "I guess I'm Princess of Friendship now", and that by season 6 they had a surplus of socially inept unicorns to learn basic friendshit again, because Twilight is all tapped out on that front. I always knew Twi was going to become an alicorn, being the apprentice to the god queen and all, but I had ballparked it as a final season/series finale/epilogue sort of thing, because where else can you go with her after that?
>>41672
I agree that the episode itself didn't do enough to justify it. Celestia sings a song about her basically graduating her apprenticeship, and it's only because she figured out a cryptic riddle about a spell with no clear purpose. The premise of swapping Cutie Marks was poorly executed too, it didn't make a lot of sense given what the show already established about Cutie Marks.