This is anime after all; gratuitous skin is expected. Besides, these outfits are magical: their armor rating is inversely proportional to the amount of skin coverage.
IMO, the only one in this picture whose new costume is seriously sexy is Nick Fury's, and I think that's the trench coat.
I can't speak for Black Widow, and the Hulk's is the same as before, but other than that they seem to be focused more on, "look at how we've exposed all these places," rather than, "sexy," "cool," or even, "vaguely practical".