The Marvel Cinematic Universe is a large and ever expanding place, ranging from New York City, to the gates of Asgard, all the way to the far reaches of the Galaxy. As this Universe has progressed, there have been two requests made by fans that have rang louder than all the rest: A black Superhero stand alone film and a female superhero stand alone film. Here we will address the latter.
Out of all the many female heroes that Marvel has access to, Carol Danvers (Ms. Marvel/Captain Marvel) has risen to the top as a favorite, and believe it or not, Marvel has already laid the groundwork for this character to be introduced and I've compiled a list of the reasons that I've seen to support this.
Carol Danvers joined the Air Force in order to pay for college and quickly rose up the ranks. As evidenced by James Rhodes in the iron man movies, Marvel can easily focus on that part of her story, anything to do with the military as an origin is a tried and true method (Rhodey, Captain America, and Falcon, not to mention Shield). But thats a simple reasons, which is why its first and now out of the way. She began working in Special Ops, which got her working alongside many superheroes, and put her up against major villains, and even the Black Widow, before joining [Agents of S.H.I.E.L.D.](series:722469). That connection could make for interesting chemistry between the characters in a live action movie.
In the Comics, Carol received her powers from a change in her genetic structure that made her Half Kree (the alien race of blue skinned conquerors). Now, with most characters with an origin like this, you might think that the studios would need to change that part of her story, or introduce her, her ascention through the air force and then into NASA, while introducing the Kree Empire, all in one movie. However, Marvel has already done most of this.
For those of you who dont follow the Agents of SHIELD television show (I dont blame you) there has been some development that makes the introduction of Captain Marvel much more feasible.
*WARING: SPOILERS LAY BEYOND THIS POINT
You see in the show, Agent Coulson recently discovered what brought him back from the dead, it was a very extensive operation that heavily relied on a serum derived from the corpse of a Blue Skinned Male Entity. Now seeing as in the episode of AoS that featured, Lady Sif, Coulson asked if she had knowledge of any Blue skinned races, she listed off a list of various species and noticeably the Kree was among them.
Also, with [Captain America: The Winter Soldier](movie:254973), we learn that in the aftermath of the Battle of New York, SHIELD has been more resources and a wider range to operate than ever before. It follows reason to believe that they would have their hands in any operation possible that dealt with a superhuman or alien threat to Earth and would be recruiting the top talent available to be among the ranks, which would include Carol Danvers.
Now I'm not saying that this "Confirms" the approach of Ms Marvel, I'm just pointing out a few things that make the introduction of that character more plausible than some Nay Sayers would like to admit.