I don't mean in the deeply sad sense, where every other movie is homogenized into the same stuff big studios have been making lately. I mean, when we see a more traditional tale of a hero doing their best to change the world, it can sometimes be interesting to imagine what would happen if various other heroes were in their place.

I've expressed my genuine fascination (and enjoyment) of Divergent before, and that's a fair example. The main character is very much a Chosen-ish One, and their mental fitness inside a military organization sets them apart and pushes them on a path to be able to stop a horrifying injustice. But what would Captain America do? He'd (likely) see the injustice pretty early on, probably do his best to stop it – and perhaps, by not buying into the unjust system, fail to be prepared for any real opportunities to stop it.

I'm not sure that's a good lesson to learn, but it's a plausible facet of reality. It's possible Himmler was trying to engage in secret peace talks when we saw Hitler's failure as inevitable (although that's fairly speculative – the point is that even the worst monsters, capable of unimaginable crimes, are capable of pushing to improve things in a way outsiders may not be able to by themselves). People with authority can always do better with it, and somewhat awkwardly, the people with the most room to improve are those doing the worst.

So Steve Rogers wouldn't have become the violence-loving enforcer... but probably also wouldn't have been in a position to prevent atrocities.

Honestly, this is just one trick among many to enhance your possible enjoyment. If it doesn't do that for you, abandon it. But when I see a hero, I see virtue and action. It's worth contextualizing what virtues would help them, and which actions differently virtued people would take – if only because it can help shape our intuitions about which virtues we ought to be cultivating to deal with our own lives.