I'm not talking about what the public already knows. I'm talking about the potential of the setting as it exists in the comics, potential that writers could draw on to make a show that would create interest in the audience. After all, Batman: The Animated Series used a ton of characters and elements from the comics that nobody in the general, non-comics-reading public had ever heard of before. Heck, that's the whole point of doing a TV show based on the comics -- not to rehash what the audience already knows, but to take the rich material in the comics and expose it to a broader audience. The key is to think of the comics as raw material that TV writers can use to build a show. The more interesting elements and characters there are in the raw material, the richer the show the writers can build from it. And Gotham City in the comics is an extremely rich setting even aside from the costumed heroes and villains, probably the richest setting in DC's Earth.