Scarlett Johansson has criticised the hyper-sexualisation of Black Widow in her debut film, Iron Man 2. I don't recall whether she criticised it, or the paycheque, at the time. I guess she's just
railing against ageing-out of those roles maturing as an actress. (thinking)
For my part—bearing in mind that beauty's in the eye of the beholder, and I'm no oil painting myself—I've never thought that Johansson was all that. I can't recall whether I watched Iron Man 2 before or after Avengers Assemble. But, if it was beforehand, Black Widow didn't make that much of an impression on me, because I didn't know who the hell she was when she appeared in the first Avengers film.
When I watched Avengers Assemble, I genuinely thought that the two twats in black were filler characters, whose self-sacrifice would bring the real superheroes together. After all, it's not that their powers were that super in the face of an alien invasion. So I was disappointed that Black Widow and Hawkeye survived.
Hey ho. It's not as if it's the most egregious problem with the MCU.