Wranglum will get reformed.
As reformations are pretty much the norm nowadays, Wranglum will finally see the errors of his ways and quite possibly break free of his mirror, without dying this time, in the progress.- Maybe he'll even go ask the Fillies, who are now fully aware of his former motives, vulnerably to help him escape from the mirror.
Alternately, Battiwings will instead.
He has more reason to. Wranglum's mistreatment of him for one. The Fillies like him as well. And he's basically the Minion with an F in Evil. Things will get much more serious once Wranglum escapes the mirror
Whenever Wranglum manages to directly attack the heroes, he tends to prove himself far more competent and dangerous than Battiwigs, and is implied to be one of the most powerful beings in the setting when at his full power. When he finally does genuinely escape, while things might not get dark, they'll likely get more dire. Miss Sparkle sealed Wranglum away
So in this trailer
, we see footage that we hadn't seen before... It appears to be Miss Sparkle pointing her mirror at Wranglum. It's definitely possible that Miss Sparkle might've been the one to seal Wranglum in the mirror for years.