I legitimately feel bad for all of you that didn't like the comic. I loved it. It brought a wee tear to my eye at the end. Far Far FAR superior that anything that is, or ever will be in the show. It just isn't possible to pull off this level of storytelling in a 22 minute Y rated show. Sombra's redemption shouldn't be a surprise. Speaking strictly in universe, Celestia realizes Sombra is much more useful putting Princess Amore back together, then getting Rekt by umbrums in prison. Seriously, can you imagine being stuck, for eternity, in a prison with the most ugly, ruthless, cutthroat, pure-definition-of-evil umbrums that you just pissed off? That's a crime cruel and unusual for a destroyer of worlds, let alone Sombra. Don't get me wrong, Sombra was not a good guy, and should have to pay back society somehow, but Celestia's been in the game long enough to know Sombra is a changed man (or pony whatever). Not strictly pt 4, but I really liked the return of the minor antagonists, and Chrysalis. I never realized how much I wanted to see them, especially after reading the fiendship comics. And Radiant Hope was such a great character. Real strife and progression with her. Just something else they could never pull off in the show. Last thing here. Thank the watcher above me that in the comics they say "everybody". Just one more reason to love 'em.
EDIT: Just found out Rabia means rage in Spanish. That would certainly have been suspicious.