Re: Who should be the "Female Lead" in the next film? Agent 13 or Black Widow?
See I read that kiss all differently. The arc of their relationship was not moving towards "Ohhh...there's some romantic thing developing here..." in my opinion.
It was moving towards these two colleagues, with totally different world views, learning to fully trust each other and positively change the other in subtle ways. That kiss, to me, was totally platonic. A kiss on the cheek just happens to be the movie shorthand way of telling us that. As things stand in the Marvel Cinematic Universe now, Natasha is Steve's BEST FRIEND. We'll see how close Sam and Steve have gotten in Captain America 3, but I expect that in Avengers 2, we'll see Steve leaning on Natasha a bit. Perhaps Hawkeye will be a bit jealous which could lead to that tension that existed between Captain America and Hawkeye throughout Avengers comic history.
Sharon should be the lead female next time. I'd be shocked if she wasn't.