Originality. Seriously, if you can’t show me something new, I’d rather you not show me anything at all.
When I create characters, I tend to focus on things I am not yet seeing elsewhere in comics. If I create, say, a Queen of Fables or a Black Alice, it’s because I don’t see a character like that when I look around.
A hundred otherwise-talented creators went out of their way to create Wolverine-rip-offs at one point. I feel that’s a disservice to your art and to the reader.