Hawkeye hasn't been given due development. They should have had Natasha brainwashed by Loki. We already got time with her in Iron Man 2. Hawkeye only showed up for like three seconds in Thor. They even added that ridiculously superfluous "interrogation" scene between Nat and Loki. Worthless. Fun to watch the actors in character, but a worthless scene nonetheless. Hell, the "interrogation" when she is first called in was worthless too.

I prefer Cap the way he is in the movies. He may seem whiny when compared to his comic counterpart, but he is easier to relate to on a human level. Just be happy, they didn't cast Shia Lebouf to play him. There's a level of whiny we don't need to see in Cap.