And part of the fun of superhero comics is that they're a total melange of genres, everything from pulp crime fiction to space opera to fantasy to horror to Westerns to soap opera to comedy. If the Justice League (at least in the DCAU) can include Martian Manhunter, Vigilante, Shining Knight, Orion, the Demon, and Adam Strange as well as Batman and Steel, then it's not that great a stretch to throw in Zatanna and Dr. Fate as well.
You know, that was one of the best parts of writing all those DC novelizations a few years back. I got to write every kind of genre imaginable--all at once: hardboiled detective scenes, space opera adventure, spooky supernatural stuff, sword-and-sorcery, superhero slugfests, even prehistoric caveman scenes with Anthro and Vandal Savage. Everything but the kitchen sink, including Krypto the Super-Dog!
And, bringing this back OT, let's not forget that Doctor Strange was a charter member of the Defenders, which, in its glory days, also included an alien herald on a cosmic surfboard, the king of Atlantis, a giant green monster created by cosmic radiation, and an Asgardian valkyrie!
Like Christopher, half the fun of comics is the sheer, larger-than-life craziness of it all.