I felt that this was probably the biggest troll from Hasbro.
David Ingram said that Hasbro forced them to make it about the cutie marks changing, to make it a musical, and to have Twilight become an alicorn.
These songs weren't BAD, per say, or too memorable, but the sheer volume made me shake my head. I felt as if nothing really happened for a while (except for some reallt disfunctional story about switching cutie marks), and then, BAM, Twilight vanishes, Princess Celestia appears, breaks the fourth wall, and shows Twilight how cool the inside of TRON looks.
Overall, the writers and artists made do with what they were given, but what they were given was simply not the caliber I had expected from a season finale. I cannot stand the fact that this is, definitively, the last episode of the season. If there wa an episode next week, it would be straight back to Brony activities 'till next week, but instead, I have to wait until season 4. Which happens...when? I'm officially taking a break from ponies for a little while. I might look on the forums, but that's about it.
My logical mind tells me that the episode wasn't THAT bad, but the emotional mind wants for me to curl up in a corner, cry, throw up, and then slowly die. Graphic, but that's how I feel. I don't know why. I just feel sick about the whole thing. In truth, this whole season has felt like a grand MLP identity crisis. They need to figure out their true direction before continuing. (NOTE: I'm not saying that the alicorn idea is bad, just that Hasbro itself needs to straighten itself out. It feels...wobbly)
Edit: And another thing: WHEN DID TWILIGHT LEARN TO FLY???