Champions is a joke in many ways, constant references included, but CoH takes itself seriously. There's jokey minor references in unimportant NPC dialogue here and there, but the CoH world is largely its own thing, and I can't think of any instances of parody in it.
I wouldn't call myself really a "DC Fan"... If anything I'm a Batman fan and a Teen Titans fan, as all the DC things I've been a fan of are Batman-related or the Teen Titans
I find Superman exceptionally boring and Lex Luthor only marginally less so, and I can't claim to know much more than the basics about Wonder Woman, nor did I know anything about Circe going in (notice she's not even on that one picture they use as the header for everything, with Catwoman standing in her place?).
Which reminds me, I'm wondering who the next mentors are going to be. The first major major patch in a few months (not to be confused with the minor major one coming this week) is supposed to be bringing a new one. I'm assuming they're going to be in Gotham, since it currently only has one mentor per side and there's a huge area of Gotham that's accessible but bottled (though that could be the new PvP zone for all I know).