@Flufux  
And everyone ignored Discord’s role in the whole thing. He not only brought them together but also encourage them and lead them to the bell. He got off scott-free. Starlight’s cutie mark theft, attempted murder of two of her villaigers time travel and attacking Twilight and Spiike with dangerous spells earned her a reward and Tempest who actively aided a dangerous warlord didn’t even get punished.
 
Sombra and Storm King weren’t immobalized and unable to fight. They pretty much got killed out of self defence. None of them were laying in front of their enemies, powerless.
 
Sure, they deserved some kind of punishment but it seems pretty unfair to just petrify them instead of doing something to try and reform them especially if one of them is a literal child.

@Red-Supernova  
As it turns out the main villain is either Chrysalis for the right reasons or Discord for the wrong reasons ¯*(ツ)*/¯

@Smart Heart  
To be fair, I never saw any interest redeeming her and Tirek before they got paired up with Chrysalis.
 
@Background Pony #FF66  
I would preferred Grogar but originally Discord way back in the day to be the main antagonist but apparently, this is not what the writers had in mind.

@Background Pony #D17F  
It gets even harsher when you read Article 37 in the UN Convention on the Rights of the Child.

@Background Pony #FF66  
I think it’s the fact that she is, from what we can tell, a regular kid. And a lot of people think that her ultimate fate is maybe a little too harsh.

@Red-Supernova  
I’ll never understand that obsession people have with Cozy, she’s just some random character who popped up in S8 calling herself a villain  
At least there is a sense of nostalgia for reforming Chrysalis, she’s pretty much the show’s main antagonist.

@Red-Supernova  
I favour both. And Tirek too. Couldn’t care less about Sombra, ‘cause he’s dead.

Yeah… well… Sombra HAD a better ending in the comics! X3

@secury  
Yes…and no. For some reason, I really don’t want Cozy Glow specifically to be reformed. I guess it might be because my love for her as a character is kinda dependent on her being irredeemably evil. It’s kinda like reforming someone like Darkseid, Frieza, the Joker or Emperor Palpatine. They just lose their appeal if they ever stop being evil.
 
The other two though, I mean maybe (but that’s a big maybe), but only if they got enough time to show their change. Though personally, I really like the idea of having the final conflict of the show to be with a Legion of Doom, even if I wish Sombra and the Storm King were there too.

@Flufux  

 
So you wouldn’t mind them to be reformed or at least put on reformation path if there was a season 10?

@Flufux
 

 
Ok fine, but in that case, you have to admit that pony’s security has some real issues.
 
Also why not just used a bell on them to drain their magic? Without their magic, they can’t be possible that big threat.
 

 
I agree, but what was the point of saying that line if the fate of villains was supposed to ambiguous?
 
As for the headcanon, I just go with that Twilight would release them if trio promised to behave.
 

 
yep

@secury
 

 
They’re still a huge threat if they escaped. Turning them to stone made it impossible for them to do so until the ponies figure out what to do with them.
 
Also, as I’ve stated before, Discord’s one line is really the only evidence that they will indeed be trapped there forever. You could easily imagine something like this fanfic could have happened later too.
 

 

 
…wait a second, aren’t you the same person who just commented on that alternate Legion of Doom picture I drew?

 
Well that were kinda empty threats after depowering them.
 

 
They definitely deserved to be punished, but I still think to be trapped forever is a little bit harsh. Even Discord got the second chance after his rampage and he wasn’t no saint before his reformation.

@asdtroi  
Discord’s line aside, turning them to stone could also be seen as a way to keep them from escaping after they stole the magic of the royal sisters, blew up half of Canterlot, were about to mutilate Spike in cold blood, and were close to destroying Equestria…and had Chrysalis ranting about how they would do it all over again.
 
Would you give them a slap on the wrist after all that or allow them the smallest chance that they’d do it again.
 
No one had much sympathy for them at that point. Whether or not they would later be unfrozen is possibly something that they would bring up later, and if they decide not to…it would be really hard to argue that they didn’t deserve it. Also, it could always be worse, I mean look at what happened to Sombra and the Storm King?

@Flufux  
But Discord’s line suggested a forever ending. And theres also the fact that Discord’s imprisonment was one of self defence as they had no other way of containing or destroying him at the time. The trio, meanwhile were powerless and immobile after their defeat. After all that time spent reforming other villains you’d think the heroes would try to use the opportunity to do the same with them, but no. They never got a second chance.

@asdtroi  
…and when Discord was defeated, still no one even hinted that he would return, let alone be reformed. And the fact that we didn’t see them in the future just adds to my point, as it would be equally as easy to assume they were released and possibly rehabilitated as it would be for them to still be in stone…or alternatively released then thrown in Tartarus. Who knows?

@Background Pony #CE61  

 
Only after we got to see that her heel-face turn was genuine in Rainbow Rocks. When the first Equestria Girls movie aired, everyone complained that it was rushed beyond all reason or were convinced that she was faking it. With the villain trio going to such great lengths to prove how evil they were, along with barely having any redeemable traits whatsoever, there’ll be no way to redeem them in a believable way when the show ends right after. If any of them were to be redeemed, we’d need at least another season to make us buy it.

@KSLDRDPL  
most complaints about redemptions wasn’t that there were too many, it was that there were too many that were done badly - mainly stemming from the pony of shadows. many people praised redemptions that were done right, such as sunset shimmer’s

@Flufux  
But thats the thing. After petrifying them Discord literally said “together forever” and no one disputed that. In the later timelapse to the future we see nothing of them leaving us to presume they are still petrified. At least with Discord it was before anyone besides Luna was reformed while the trio was post Starlight and reformed Discord.

@Ponylooker  
Like the Storm King?

@asdtroi  
What makes you think they were treated any differently than Discord was? When he showed up he was presented as a straight up villain and was then turned to stone with no hint of a reformation in sight…and yet he was reformed about a season later. The ending leaves it very much open to your personal interpretation whether they eventually unfrooze them later or left them there to rot. So no, Discord was treated exactly the same as the villain trio was.

@Red-Supernova  
Can you blame them? Being only a child.

I kinda wish Chrysalis had more but everyone seems to favor Cozy more.

See, Cozy? The fandom does care.

@Dustcan  

Well I mean Sombra was pretty much vaporized. He’d probably love to be a statue right now.