According to Comic Book Movie on Sunday, cameo appearing Stan Lee made a statement in regards to a possible solo "Black Widow" movie. Lee has been credited as Marvel Studios' film producer, but has had limited involvement as of late. However, he does tend to share his opinion when it comes to future comic book movie prospects when it comes to Black Panther and Doctor Strange.
A solo "Black Widow" movie has been a desire by many fans. Some may think a female lead movie would allow for the kind of "feminist breakthrough" as fans may have come to expect, but this wouldn't necessarily be the case. Considering at this point and time she's rather popular already as she is prominent in the current films and bringing her to light in her own movie would make her overqualified. Basically, the strategic move to make her female-centric would have little impact in popularity. Basically, it would be too easy.
"We haven’t made a Black Widow movie but she’s been in some of our movies, and she will be featured more prominently as we move forward. And the chances are she will have her own movie because eventually all the superheroes are going to have their own movies. They are already working on Ant-Man, Dr. Strange and the Black Panther and there are others I am not allowed to talk about."
After "Captain America: The Winter Soldier" had hit theaters, the demand for Black Widow to have her own spin-off flick has risen significantly and this was even further reinforced by Scarlett Johannson's own solo lead female movie "Lucy." Though the demand may be high and if the green light is given to do a solo film, "Game of Throne's" Neil Marshall is ready to helm such a film.
Marshall does however care more about the aspect of a female lead movie and it's not entirely significant to him that the person even be a super hero. The director did mention that it would thrill him more to work with a character that didn't have powers and obviously Black Widow would qualify.