Yeah, it certainly was amazing. It felt like a two-parter for a moment there, but I think Discord would need to do something big, like prevent himself from being imprisoned somehow, to call it in.
And yes, it was indeed a breath of fresh air to see once again what Fluttershy's really all about. Seeing somepony give Discord an actual shot, rather than just going, "Okay, too many pranks. Element blast this sucker. (*Coughcough* Dash *cough*)" drove home just how big a deal showing someone that they care really is. True kindness. Besides, it WAS Discord after all. Reforming him was NOT going to be easy. Celestia didn't bail out from sticking around during his reform process for no reason. (If asked why she wasn't staying, I can almost imagine her saying, "No thanks, I value my sanity.") XD Probably my favorite 'Shy episode so far.
True, I can see the convenience behind that for the big "cure the psycho" cases. But reform's such an ugly word, when used in this particular light. At least to me it is. To magically alter someone's way of thinking against their will just feels like outright manipulation. Blek. I'd rather see something that teaches the importance of why someone would need to change, and allow them to understand it themselves. Basically, magical reform just makes me think 'brainwash', instead of, what one could call... 'rehabilitation' reform. But if something could magically 'teach' the importance, that's great. It's just mental override seems like the decimation of free will and choice.
Aaaaand, if someone just outright refuses to change, even after fully understanding things... well there's always imprisonment...