Great answer. But the only reason Captain Marvel isn't listed is because he is not as famous as the other heroes; Superman, Batman, or Spider-man. Back in the 40's CM was the most popular and who I think was the greatest superhero ever, today not so much. A movie is still in the development stage and will be out in a few years, that is what CM needs to come back into the limelight!
I'd love to see it but I'd be worried about how he gets portrayed. I think he's like Sir Galahad - the purest of the pure - because he's what a young kid imagines a superhero to be. But I don't really agree with the writers who put that young kids mind into Captain Marvel.
To me, he's an adult, but a very innocent one. He's not a kid in a superhuman body though, and he should be able to think like an adult. He's the guy who every woman's mother wants them to marry, but not necessarily the women themselves. He'd be friendzone or big brother material straightaway - (at least until Billy Batson started growing older).
Both Captain America and Superman I think have bit more ....not masculinity, but maybe, sexuality about them? I can see chicks wanting them. I can't see it with Marvel - despite him being Supe's equal. Like I said, maybe I'm confusing 'pure' with 'idealistic' - but I reckon they come together. How else would a kid view an adult superman?
Marvel - he's the purest hero in my book.