Vision: While I'm not sure myself if Loki did something to get them to hate one another, I do know that a reasonably successful mission like this is the tonic that they need. Also, I have a fair idea that you're heading somewhere with this look at Sombra's past.
Originality: Having the heroes bicker like Avengers or members of the FF is a nice way of melding the mythology of Mighty Marvel into the mix. While it's true that Twilight and the others didn't always get along, the strained friendships we see here will make victory all the sweeter.
Technique: While I don't usually associate Cloudsdale with super-hero fights, the description of the battle (as well as the stakes) helped sell the idea.
Impact: While it's nice to see a victory, it seems that the business with Sombra and whatever Spike found will certainly affect things.