Synopses, for those who aren't as in the loop.
From The Hub and Zap2it:
Princess Celestia tasks the ponies with reforming Discord, a mischievous spirit of disharmony, but Fluttershy is the only one who is willing to give him a chance.
From FYI Television:
Princess Celestia has decided that the rambunctious Discord needs to be tamed and commissions the ponies for the job; Fluttershy believes that Discord deserves a second chance but she faces opposition as she is the only one who thinks so.

oh gawd
DO NOT WANT.Seriously, that's one of the worst possible things that could happen to this show.
First, Discord is an evil god of chaos. He
shouldn't be redeemed, under any circumstances.
Secondly, this'll make Fluttershy into a huge Mary Sue. She's been my least favorite of the Mane 6 for a while now, mainly because I find her personality to be too sweet and angelic to be real. Nopony is a Disney Princess in real life. Ands redeeming a supposedly irredeemable character is going to make her go a couple notches up the 'sparkling white pureness' scale. Note to writers: character development does NOT mean making them have infinite kindness and mercy. It means fleshing their character out and making them
more than just a stereotype, something I don't see happening to Flutters anytime soon.
Thirdly, we've already had one major villain get redeemed: Nightmare Moon. Two is pushing it. If this keeps up, by the time this season is over, we'll have G3 back.
Fourthly, he's still stuck in stone. How's he going to get out? Are the Mane 6 going to lose their connection to the Elements of Harmony all of a sudden?

Fifthly, I hang out on the fanfic sites, and this is going to make a huge spike in FlutterxDiscord. *throws up*
This episode will never be canon in my brain.

I agree about Fluttershy, she's overrated in the fandom IMO. I do have a shirt with her on it, but the "Yay!" part of SR was a classic. She's actually the most stereotypical little girl show character, which makes it odd that she has such a large and devoted following.
Couple of small things I disagree with, though:
Discord is not evil. He isn't good, but he isn't sadistic, nor was his goal destructive. I agree with how The Hub's synopsis describes him, although it is perhaps a bit understated.
Nightmare Moon wasn't introduced as a villain and then redeemed, she was introduced as a villain
to be redeemed at the end of the same episode (basically the same episode, anyway). Plus, now they've actually blown up a villain so that makes up for it in my mind

Anyway, on to the matter at hand.
I think it depends on who the writer is... if it's one of the better ones (or the new guy!) I think they could pull it off.
Buck. Just checked. It's Polsky (FPK, OaB, TMPP). Crapcrapcrapcrap! He's written one terrible episode, one slightly above average episode, and one slightly below average episode.
Not who I would've picked to write for Discord. Ever. Never ever ever. Oh well. If even Merriwether can redeem herself, perhaps this will be his chance to shine above the rest....
I was really hoping it would be McCarthy (Ds, CotC, GIYC, PoO, LZ, SaE, HaHD [nobody is perfect...] ACW Pts. 1 and 2, and TCE Pts. 1 and 2 [very underrated episodes, IMO]). Sshe's done some of the best writing (and actual development!) for Fluttershy (Ds [Dragonshy]), plus she's done pretty much all of the breakdown episodes (PoO, LZ, SaE) and, aside from HaHD, she's managed to avoid stereotypes or use them effectively.
Well, ****. At least Larson is writing the finale and we're getting more of Powell after this (Just For Sidekicks, perhaps the resolution to WA).
I guess this will be their way of wrapping up Fluttershy's story before... whatever happens. I believe each character will get their moment in the spotlight and achieve something along the lines of their original goal before the end of this or the next season (Rarity might become a more significant designer, Pinkie might... well... maybe becoming many of herself was her moment.., Twilight will achieve that "next level", etcetera. This may extend beyond the Mane 6 as well... SiP, for example, may have been the fulfillment of Scootaloo's character).