he's only corrupted because his Evolution Engine can change his thought processes, and the Evolution Engine only cares about making him able to defeat his enemies. And it changes the way he thinks as he evolves, making him care less and less about collateral damage and loosening his morals.
Yeah, like- Varic himself, who is very clearly traumatized by what the Spellbinder timeline's Starhammer did to him and does not trust him at all, outright states that he does think it's entirely possible that Starhammer could remain an outright hero and genuine force for good as long as nothing sets the Evolution Engine off.
He's been deactivated, yes, but he was never fully destroyed- and his original creator, who very clearly regrets how things went down and did initially want to save him from his own fucked-up superpower mode, is right there with a lot of time and potential resources to work on him.
I could very easily see a version of Starhammer with the Evolution Engine removed and set back to a less homicidal galaxy-conquering baseline state showing up as an ally later in the series.
Honestly, I think it would have been really interesting to see Starhammer and Varic talking at some point after Varic saved his wife but before they fought and the Evolution Engine went off again.
And then Varic just shows up like 'hi, I was literally chosen by the will of the universe itself, the fundamental force that underlies all reality, to tell you that you cannot handle it and IT IS NOT FINE'.
Mell: /non-committal hand waggle