Someone wrote on Reddit years ago that a fascist titan-of-industry Lex Luthor could operate as a foil to Superman's righteousness: Someone who does horrible, unethical things that are fully legal thanks to politicians and courts that he has legally bought off through a system that has fallen to the influences of money.

Superman would have to make the decision: Do I break the law to stop someone who has broken no laws, who has the government's full backing, or do I become a vigilante and an outlaw in service of the moral good?

In a way, this is how they handled Captain America and it resulted in taking an otherwise boring, one-dimensional boy scout and updating him to modern sensibilities about justice.