I would love to see a ScarJo Black Widow movie.
Marvel has plenty of interesting female characters, it would be nice if they would give one of them a chance and give her a movie.
I would think that after the success of Hunger Games, studios would be more willing to take a chance on female lead action movies. We've had plenty of proof over the decades that if the movie is good, people will come.
EDIT: In the last few years, we've also had Snow White & The Huntsman, Brave, and Salt. All of which were in the top 25 movies of their year, and made over 100M $.