I guess that this puts discord on the “token bad guy” (or should i say chaotic neutral). He still loves chaos, but now he have a conflicting motivation to help the forces of harmony. If they write him correctly this could make him a very interesting character.  
Though i don’t think that they really got all they could from him being a straight up villain. More fanfic material for us a guess.

I’m still a bit ticked off about King Sombra.  
Totally could have done more things with him.  
Considering how they killed him,  
there’s a distinct possibility he could come back,  
if they reassemble the pieces somehow…
 
Maybe give him some good lines.  
And give him a better voice actor.  
Like Tim Curry.  
They don’t even have to give him that many lines.  
Just… Tim Curry.

@Background Pony  
@Trickquestion  
Another theory might be that you guys are overestimating Discord’s power.

I am going to be disappointed with Discord. How do I know this? Because he either is a gag, or his powers resolve everything with a snap of a finger.

@Trickquestion  
Or, we could go the more chaotic route where discord shows up at the beginning of an episode and gives the heros a banana, then says he has done his part. Then near then end of the episode, when all hope seems lost, they bring out the banana and it turns out the new villain is allergic to them, and the main six blast him/her while he/she is distracted

Here’s how it breaks down in my eyes: Discord changed sides because he came to care for Fluttershy. If he cares about Fluttershy enough to radically change his behavior to stop her from being upset with him, he obviously cares enough to protect her from anything that might cause him to loose his new and only friend.
 
Cue next threat that requires the Elements. Either Discord dosen’t care, keeping him put of the fight and rendering all of “Flutter On” completely pointless, he jumps in immediately to protect his friend and we have no episode, he stays back until he feels Fluttershy is really in danger, destroying any tension or threat the villain creates, he gets beaten, which would be an even bigger display of the Worf Effect then Celestia being beaten, or he is simply never mentioned, which creates a continuinity snarl.

@Itsthinking  
I can see that too.
 
That’s the best part about Discord, unpredictability is part of his character.

@Princess♠Molestia  
I could see him being like “oh NO you didn’t just try to spread more chaos than me” and then turning his “competition” into something ridiculous.

@Trickquestion  
The question is. Would he even bother to help?
 
He’s a being of chaos, so ignoring an issue such as, say, Nightmare Moon’s return or something, wouldn’t be out of question.

@Trickquestion  
Wonder if they have someone as powerful as him in the opposite direction lined up.

I’m curious as to how they’ll write around the massive power imbalance a good Discord creates. I mean, if Discord had been good during “Canterlot Wedding” and “Crystal Empire”, he could have just turned Chrysalis and Sombra into pool toys in less then a second.

It’s been said a billion times by now but…
 
Chaotic Neutral. It’s a thing.

This is EXACTLY why I loved the idea of Discord being reformed.
 
@Itsthinking  
I think it’s more because he loved the show and/or the fandom then he thought.

I hope he shows up more in S4.

So I’m guessing they realized they could get de Lancie more often then they thought, huh?

Evil alicorns, you say…?
 
Who in particular might we be talking about, hmmm?

That’s…slightly ominous.