Maria Hill
In the comics, Maria Hill is a much more interesting character than she is in the movies. As a hero-hater, she often clashes with the Avengers and Nick Fury. Movie Maria is probably more likeable, then, but she doesn’t have the personality and layers of the comic book character. The version played by Cobie Smulders is just Fury’s loyal stooge.
That would be fine if she was fleshed out a little. With some more work, Maria could become the Avengers’ indispensable right hand woman. Unfortunately though, she has one simple purpose in the movies: to spout exposition. Remember how Sigourney Weaver’s character in Galaxy Quest complains how her only role is to read out what the computers are saying? That’s Maria Hill in a nutshell. She’s hardly got any scenes which don’t involve the character relaying information to either Nick Fury or Captain America.
After three movies and a bunch of appearances in Agents of S.H.I.E.L.D., Maria should have some more flesh on her bones by now. Seeing as she hasn’t appeared since 2015’s Age of Ultron, though, it looks like the character is now… wait for it… over the hill.