I myself didn’t run Champions, but I played with a consistent group for about 4 years. We were all avid comic buyers, so a lot of inspiration came from Teen Titans (George Perez and Marv Wolfman), The X-Men (Chris Clairemont and John Byrne), and a scattering of John Byrne era Fantastic Four. There was a bit of influences from early 80s anime as well, however since all of us came out of the highschool wargaming club, the Comics Code was a loose suggestion.
I ran Fantasy Hero, and my influences were the Deryeni books, and other politics and violence heavy fantasy trilogies of the time. I bounced off of Tolkien, so his influence was minimal.