When it comes to them, bad isn't just cool. It's understandable. It's worth rooting for. Maybe, sometimes, if you let the boundaries blur enough, it's even right.
I can't wait for the movie to be announced. (They better make one.)
Whatever their identities, the things that make a villain interesting remain the same. We want to understand their motives (as dark as they may be), to see what makes them tick, to maybe get a glimpse of the humanity underneath, if that still exists. If not, we want to be impressed by the scale of their ambitions as they become the person we love to hate.