The comic proposal was very broad. How about a community for the actual comic nerds, people who wants extensive information about the superheroes and villains in the biggest universes of fiction and fantasy, DC and Marvel. This community will help people who wants to know more about the character or the story line. This will be very useful for people who wants to watch a comic-based movie and has no idea about the back story.
Both fictional worlds are on-topic on Science Fiction and Fantasy SE.
DC Comics has a tag with more than 500 questions (with more than 93% of them answered), and a bunch of smaller tags for the movie universe, the animated universe, specific characters and specific storylines.
Marvel Comics has a tag with more than 900 questions (with more than 94% of them answered), and a bunch smaller tags for the cinematic universe, specific characters and specific storylines.
I don't think we need another site for these topics.