drunkonduty's link above is fantastic (for me). As have been all the answers so far, to be sure. But that link, with the 5 or 6 viewpoints/essays given, really helps crystallize what I was wanting to know vis a vis worldbuilding and the comparison between fantasy and superheroes. I was of a mind that I wanted to create a world(s)/campaign that had superpowers but not have it be focused on superheroes, while at the same time not excluding them. I also wanted to have elements of urban fantasy. This discussion has helped me see that I probably do want to go with fantasy and incorporate my other elements into it, if I can (and discarding stuff that ultimately just won't plausibly fit). My reluctance to embrace fantasy is probably most strongly influenced by my own relatively shallow direct experience with it.