I think you're starting from a falsehood, or at least missing/ignoring certain facts. Yes, Superman and Batman are two of the three people come up with the minute you say "superhero." The other being Spider-Man. But in part that's because they've been around long enough to become cultural icons. They've had the constant exposure that others have lacked.

But if you grew up reading Image, for example, you might feel differently. Or Wildstorm. Hell, read Wildstorm enough and the question "female superhero" automatically comes back with "Jenny Sparks" and several others right behind her. Read Image enough and you'll get "Fathom and Witchblade." We can also take a step to the left and get "Promethea." In the same way, the answer to your first question might be "Kevin Matchstick" or "Prime" or "Mr. Majestic" or "Savage Dragon."

Your answers apply for our age group, with our reading backgrounds. We grew up on Marvel and DC. The field has changed a bit, though those two are still the hoary old eminences. It doesn't mean there aren't female superheroes equal to Wonder Woman in stature. It just means they haven't had almost seventy years of exposure.

I'm not saying the field isn't skewed toward male heroes. It is. But I think there are female heroes comparable to Wonder Woman. They just haven't become iconic yet.