Joe Quesada has been in charge of Marvel Comics for over a decade. His current title is Chief Creative Officer of Marvel Entertainment.
There is a big controversy over his recent statements over saying that there isn't a female character in the Marvel Universe that he can make a big tent-pole movie out of. You can read about it here: http://goodcomics.comicbookresources.com/2012/05/21/she-has-no-head-dear-marvel-stop-ruining-everything/
I think he is right, but not for the obvious reasons. I think this is an area where Marvel Comics simply fails, especially compared to DC Comics.
The majority of the really awesome female characters fall under the X-Men franchise and those rights don't belong to Marvel Comics and won't revert until they quit making crappy movies. None: I believe this is a big reason why the X-Men have remained important even when they have had crappy writers and confusing storylines.
For the record, I don't think that the Black Widow, Hawkeye, or Nick Fury can carry a blockbuster movie. These are awesome characters, but not quite stars.
I think that a good comic book movie has to have the following three points to be great:
1. A solid, but simple origin not tied to other characters. For example, you can describe the origin for the following characters in two sentences: Captain America, Thor, Iron Man, Batman, Blade, and Superman.
2. The powers of the super hero should be interesting visually for the movie to be awesome.
3. The hero must have interesting villains.
Sometimes you can get away with only two out of the three, but those movies don't tend to hit the big time. I think this is why the Hulk movies usually fail. His villains are boring as hell. I tried to think of awesome female characters from the Marvel Universe that would fit under my suggested paradigm. I couldn't find any off the top of my head that weren't somehow connected to the X-Men.
I even checked this list to make sure I didn’t miss anyone: http://marvel.com/universe/Category:Women
Note: I did not include any X-Women past or present. Or characters tied to the X-Men. That includes Rogue, Storm, Phoneix, Psylock, the Scarlet Witch, and Dazzler.
Special note: I will send seething hate to the first person that suggests Squirrel Girl.
Here were my top contenders.
Monica Rambeau / Captain Marvel has a simple origin and interesting power that I bet would be awesome to see on screen. The problem is that her writers have shat on the character for years and allowed other characters to steal her hero name over and over again. (She has had like 3 superhero names stolen from her.) She also has no villains worthy of the name. I love this character. The proper writer could make her a star. Don't believe me? Think about what Bendis did to Luke Cage.
Spider Woman has way too complex of an origin story. I can't even keep it straight. Her main villains is Hydra, which could connect to Captain America, but overall are boring without a Red Skull type character. I also think people would expect her to be more tied to Spiderman, which would be impossible due to rights and wouldn't make sense history wise.
Ms. Marvel has a simple origin story, but her history is crazy and complex including the time the Avengers let her get date-raped drugged into another dimension. This history could be streamlined, but alas her main villains are connected to the X-Men. How could you tell a proper Ms. Marvel story without including Rogue?
She-Hulk is a fun, dynamic character. The lawyer bit would be fun to put into a movie. However, her origin is tied to the Hulk and she doesn't have her own villains.
Jennifer Hale is a cool character as a sorceress, but she doesn’t even have a super hero name. She also has no villains. She is mostly tied to the Swamp Thing.
Songbird is kind of a cool character. Her origin story would have to be simplified. I bet her powers could look awesome on screen. However, she is the classic good girl gone bad for a while. The problem is that she is only interesting when she is trying to be a good guy stuck with the Thunderbolts. (I do think a Thunderbolts movie would be awesome and a number of those characters are interesting female characters.)
The problem is that the Marvel Universe needs better female heroes. Half of the readers of comics are women these days if judging from the fan fiction forums. You want those readers Marvel Comics? You had best start creating characters that inspire them rather than retreading yet another version of Spiderman, the X-men, or New Secret Avengers. This requires the artists and the writers to make new characters for this generation.