Actually, Campbell admired Star Wars when he called it a modern myth. That is, he admired how George Lucas took Campbell's Jungian advice on the need to update religious myths, to engage with the archetypes in a fresh way. For Campbell, what's universal isn't the traditional story but the set of archetypes or the existential themes.

A naturalistic religion would be a noble practice that's based on an atheistic mythos, on a story about how to achieve what I've called godless honour. The religion would be consistent with scientific knowledge. Nietzsche's candidate was social Darwinism, roughly speaking. I reject that, and posit pantheism, existentialism, cosmicism, humanism, the Promethean war on nature, and so on. (I'm still working this out, of course, and don't claim to have all the answers.)