As I hope my previous post made clear, I liked the movie and will probably see it again.
But, dear God, is the character a Mary Sue.
1. She's retconned as one of the most powerful characters in the universe. (Yes, it is a problem that Fury never called her before, though a later writer can always say he did and she was too busy to take the call.)
2. She is so important that she gave the Avengers their name. (Why she was called Carol "the Avenger" Danvers, we haven't a clue, because we never saw her do anything that would inspire anyone to call her the Avenger.)
3. She immediately becomes Nick Fury's pal. (She and Fury are shown laughing together in scenes that seemed wrong to me. If I'd been directing, I would've told the actors to play the scenes more subtly.)
4. She doesn't seem to have any lovers in her past. (Perhaps because she's too amazing for any ordinary boy or girlfriend.)
5. Everything we know about her past is about things she did for herself instead of anyone else. We are supposed to believe she was a great friend because her cool black friend says she was, but we have no idea what she ever did that made her a great friend.
6. She gets her abilities not because she earned them like Wonder Woman or Batman or deserved them like Green Lantern or Captain America, but because she's the one who's standing there when the experimental power source explodes—and unlike many of the characters who have a similar origin, she wasn't even responsible for creating the thing that transformed her. She simply gets awesome powers because the writers wanted to write about someone with awesome powers.
As for how her story is a tiny bit racist, her awesomeness is established with the testimony of Nick Fury and Maria Rambeau—she's so cool, black people look up to her.
Okay, that all sounds like I didn't like the movie. I did. But I really hope the next Avengers movie manages to make her less of a Mary Sue.
ETA: Extra point on the little bit racist: Marvel had a black female Captain Marvel for a few years, but they sidelined her in favor of the white woman.