Unless it’s lack of balls…and you can take that either way you like. That she can’t catch a break because she doesn’t have literal balls like her male counterparts or because DC/WB/Hollywood/Whoever Is Really In Charge of These Things don’t have the metaphorical balls to simply make her damn movie.
And why not? Frozen and Catching Fire are blowing the doors off at the box office and nobody cares that they have female leads. They just care that they’re damn good movies. Smart movies. Movies that respect their characters and their audiences. And in the case of Catching Fire a movie that is vehemently faithful to its source material.
But we still somehow live in a world where “whoever is in charge of these things” thinks the best way to introduce Wonder Woman to the world is as a bit part in Superman/Batman.