@Prince Mainesly
Sombra was still almost a thousand years older than any of the Mane 6 were when they died. And he kinda had to die to keep Equestria safe from him, for reasons I say below (imagine trying to do what you said with Palpatine, Sauron, Voldemort, or Ganondorf).

In all seriousness, really how else could his threats have been stopped without seeming too hard to swallow? (I posted this image as a joke)

Celestia and Luna tried sealing him away but he was able to cast a curse that made the Crystal Empire disappear until his eventual return a thousand years later, and then they lost their memories. He could easily have done this with Canterlot… or Ponyville, and then there’d be his thousand-year return hanging over them by which time the Mane 6 would no longer be around to stop him.

As reforming him goes, remember the fact that he was killed the first time by a wave of love and light that all the other ponies in the area were exposed to and it didn’t even hurt them, only turn them into crystal ponies. Anyone evil enough to die by the power of love is likely not redeemable. Unless they decided to go with his comic backstory of him being an umbrum weak to its power simply for what he is rather than being an evil pony, but that already contradicted his personality from the murderous psychopath who licked his lips when he was about to impale Spike. Still a good story, just not canon with the show, in which he is the most evil villain in the series.

And needless to say, where Chrysalis was shown in Season 8 to be unable to do much on her own, Sombra did act on his own each time, other than brainwashing ponies to do his bidding. He’s not only very powerful but very intelligent (though this is dumbed down slightly in S9 with his Bond Villain Stupidity). So leaving him on the loose where he can plot revenge and possibly get it down the road past the final episode… Yeah, not an option. (They actually DID do this with Frieza in Dragonball Super, after people were similarly disappointed with his revival and death in Resurrection F (whose story is mirrored in the Golden Frieza Saga, though with significant differences), and while he may be leaving Earth alone he will still be taking over and destroying planets)

All in all, Equestria is definitely better off without him. He was the most evil and one of the most dangerous. (Though Discord would be more dangerous if he was as evil and serious as Sombra)

(And also I love that, despite the point of view of some neighsayers and even some fans who are either ungrateful of what the writers do or genuinely think they shouldn’t be there (which is sad), that FiM didn’t think itself too childish to do what G1 did at least twice, and several Disney movies. Sombra was the first to show that even though the Storm King and the Mean 6 followed.)

So, even though they revived him just to kill him again, we did get more screentime and lines from him, and his personality fleshed out a bit more. He got one more chance to shine as main villain (solo, where Chrysalis, Tirek, and Cozy Glow shared the role in the final), and he did make an impact by destroying the Tree of Harmony, as well as prompting more security measures in Canterlot and a whole episode dedicated to the aftermath of his attack. And we got to see him fight Discord, and he pretty much showed that the Mane 6 had the power inside them. (Though this raises the question, why did they need Rainbow Power to beat Tirek?)

HA! that’s a good one! ^^

lol this is so good i laughed for 3 minutes and i couldn’t stop XD

AH HA HA HA HA HA HA HA HA HA AH yeah he was better in the comic.  
A lot of villains are better in the comic.

@Background Pony #A72A
 
if he is apart of equestria then yes even him. if not then idk, haha

@Prince Mainesly  
Not even Sludge?

To Horse God, all horses deserve life.

I’d Revive Sombra, sure. i don’t think he’s all that scary or anythin. :/
 
Not to kill him again of course. maybe some nice rehab or therapy. nopony needs to die in equestria by any means.