Unfortunately it seems like if new characters are going to join the team, they're going to be white males. Because there's such a shortage!

I would love it if Natasha wasn't the sole female representative on the team.

That's actually why I'm concerned about Natasha being in Winter Soldier. I think it would be a mistake to make her history about her relationship with him, especially since that isn't the case in the comics. I don't see how reducing her history to her relationship with one guy, whether it be romantic or platonic, can be anything but a detriment to her character. That goes for her relationship with Clint, too. I'd squee the theatre down if they got together, but I don't want her to be reduced to 'Hawkeye's girlfriend' either. Give her agency, give her an arc. I thought The Avengers showed her go from being mainly motivated by her desire to save Clint to fighting to save the world, and that was a good arc for her.

I'll stop before I go on a rant about the importance of having women and other minorities be the stars of their own stories.

the majority of any new Avengers would be white males. Falcon, War Machine, Black Panther and Luke Cage are all black. Wasp is a woman, and Whedon was rumoured to have wrote her into his first Avengers draft, until Marvel told him he had to work with Hawkeye as thy had already set it up through Thor. That's why Hawkeye's role was so small, Whedon never originally planned to have him in the movie. Captain Marvel is a possibility as well and she is female. Doc Strange and Ant Man are whites and so is Bucky, but the latter two may never feature in an Avengers movie.

Natasha has history with Winter Soldier in the comics (she has history with lots of guys, true) but I think it would be a pity if they took the chemistries that have already been established in the movies and failed to go forward with those. I'm not saying we have to have Clint and Natasha get together plainly, but, oh, the chemistry and the continued potential UST of those two--don't chuck it all just to be "closer to comics canon"!

I recognize this too may be an unpopular opinion among Avengers comics fans. ^_^

By 'history' I meant her backstory, ongoing character development and continuity rather than her relationships. Natasha's history does not revolve around the guys she dates. She has a long, complicated history of her own, and I think it would be a mistake to reduce that long history to her affair with one guy.

Eh, I view the comics and movies as separate universes, so I say canon, schmanon. ;)

Natasha's history does not revolve around the guys she dates. Agreed--she's far more complex than that alone, even if romantic entanglements are some fans' focus.