In my opinion Carol Danvers can become Marvel's top solo female hero, like Wonder Woman at DC. Marvel changed her name from Miss Marvel to Captain Marvel, gave her a new costume, and a new series, and she is currently starring on the Avengers EMH until its canceled. And there was a rumor about her popping up in the Alias AKA tv show. I think she could be a bigger character in the comics and in the movies. She could be on the same level movie wise as Captain America or Iron Man. And Marvel should see that, and probably does, and should jump on that as soon as possible.
And DC should have already made a Wonder Woman movie by now, I think its the swim suit costume and cheesyness from the old campy series that is holding her movie back. But we might be getting a Smallville styled Wonder Woman show soon. I hope its more like a Wonder Woman Year One than a no costume no powers thingy.
I like the idea of introducing her in a film like Thor 2 or 3 and showing her working on a part of SHIELD called SWORD, that deals with alien life. Started because of Thor, Loki, and Loki's alien army coming to earth. And showing Mar-Vell, in his human form too. (But you still don't get him being a heroic superhero in costume.) And then giving her her own movie that also has Mar-Vell in it too. I'd be fine with it just being her cameo in, lets say, Thor 2, and then her running into Mar-Vell (alien) on a mission.
Showing her first as a capable SHIELD/SWORD agent and pilot helps establish that she isn't just a hero because of the powers or because of the costume or because Marvel wanted a female hero. She is a well trained and heroic human first, and then becomes Captain Marvel later.
Oh, and I think in dealing with Mar-Vell and Carol, I think it should be established in the film that Mar-Vell is a hero to his people. Like a Captain America to the Kree, and other planets. But make the film about Carol. That way its almost like a legacy being passed down of his status as Captain Marvel.
And I think it could be a fun idea to introduce his relationship with Annelle from the Skrulls, and that she gave birth to a Kree/Skrull child. Hinting at Teddy from Young Avengers. And at the same time show Scott Lang working in Pym's lab and mention/show his daughter who later becomes Stature. Hinting at future films about the Young Avengers.
My ideas for the film follow the plotting of Thor 1, not GL. Just to clarify something no one was asking about. I heard that Mar-Vell's death might come across like Abin Surr's in the GL movie. And have no impact. But if the story follows a similar plotting as Thor and my idea it would work I think. The movie starts and Carol is already in her Captain Marvel costume/armor. She is in the middle of a giant battle against a massive alien robot in the middle of a big populated city like New York or LA. She has powers and is trying her best to stop the robot and save civilians. Cut to hours ago, maybe even two days ago or something. Now we actually meet Agent Carol Danvers, she works for SWORD which is a devision of SHIELD started after the alien Invasion in New York. She is also an accomplished pilot. On a mission she runs into an alien on the run from other aliens. (quick summary.) He is a soldier, Captain, named Mar-Vell. She helps Mar-Vell against Yon-Rogg and his rogue Kree soldiers. It is revealed to her the Kree's involvement in Earth matters, secret involvement. We also learn and see how heroic Mar-Vell is. He is like a Captain America type. Carol shows she is a capable agent too, without powers like Mar-Vell shows he has. She holds her own against the Kree and even against the giant alien robot when it shows up.
While fighting the giant alien Kree Sentry robot Mar-Vell sacrafices his life to try and stop the robot and in the process gives his powers to Carol.
Now Carol has the powers and costume. She starts fighting the alien robot and this is where the movie started. She ends up saving the day and in public too.
This idea would show her first as Captain Marvel to let the audience now she is the star and will get powers. But then we see her without powers to show that she is more than powers, but while she has no powers Mar-Vell has powers. The moment Mar-Vell looses his powers and dies Carol gains the powers.
Similar in plot to Thor too, and it worked there. Thor starts out with powers facing the Frost Giants. Looses his powers and is banished to earth. Regains them in the last half of the film and faces the destroyer and Loki.
Only in Captain Marvel, while Carol has no powers Mar-Vell does. So someone is always Captain Marvel in the film.