Ok, so here are some of my thoughts on the episode.
So, I find it ironic how in the end Discord was only defeated because Fluttershy lost faith in her attempts to reform Discord through kindess. See, I think it's pretty clear that Fluttershy is too socially naive and kind to actually form a gambit like Discord suggested, she wasn't using "I'm not your friend anymore" as a tactic, she was just frustrated and was being honest. She was hurt. Discord's gambit was that Fluttershy would just foolishly keep giving him more kindness in an attempt to reform him, and he would have complete control over her. It wasn't until Fluttershy finally gave up that he realized he liked Fluttershy's kindness, he liked having as a "friend", and it was only then that he realized it was his fault he couldn't have friendship. After all that time he finally realized the true importance of friendship. Now, this is ironic because the only reason Fluttershy succeeded was because she thought she had failed.
Now, if Fluttershy never even tried she would have failed, but if she just kept at it forever she would have failed equally. This incorporates some elements of "Achievements in Ignorance" where Fluttershy manages to accomplish a task anyone with more experience in the field would find to be impossible simply because she believed it was possible, but while she is naive, she isn't stupid. She isn't going to endlessly pursue a futile cause. That duality is what caused her to win in the end. Also, we know Discord's reform is genuine because he was at a point of greatest power when he was reformed, he would have had no motivation at that point to fake being reformed.
I think the message that came out of this is very mature and important. Fluttershy is, to say the least, not the most socially cunning pony, but she still has her kindness, and that's all she needs. Ironically enough that theme came up in a seminary video this morning. All she needed to do was reach out to Discord and give him a chance, something anyone can do, but no one did. Fluttershy managed to win Discord over not by being manipulative, but just by being herself, sticking true to her standards and integrity, and giving kindness even to some one who didn't really deserve it. Kindness isn't a technique she uses to manipulate, it's just who she is, she is the only pony able to acknowledge Discord's flaws, but still look past them and treat him as a person. I saw Les Mis back on Saturday, and the same themes can be seen in that movie. On another point which shows even more maturity with writing, Fluttershy's giving up shows us that there are times when for everyone's sake we need to stop being "nice" because, like seen in Putting Your Hoof Down, sometimes people will take advantage of it, and in the long run it won't really help anyone, leaving the giver drained and the taker deprived of needed personal growth. This episode does well to develop Fluttershy's character, really building up her as the element of kindness and making her a more admirable character, not just a cute one.
Regarding other points in the episode, I still don't get why of all times to reform Discord Celestia does it now, and it's a bit disappointing that Discord is presumably no longer a villain. Not a nice thing to think, but this is entertainment. I found Discord to be in character, one that made sense, and that the progress of the episode made sense, though Discord's conclusion and reforming were a bit unrealistically sudden. Overall, the episode exceeded my expectations.