I think what you're saying is, and correct me if I'm wrong, that if the movie isn't a good enough story, it won't do as well. I think that's far more likely a cause than sexism, as other women led movies have shown. Wonder Woman was a good movie. It did well. I think they should market it as any movie that starred a man--and not play up the gender thing. In Natasha's case, it never was a thing at all. She's a hero that happens to be female. Her gender should have nothing to do with anything.