8) Cap vs. Hawkeye – Captain America: The Winter Soldier
Of all the Avengers, Hawkeye is easily the character with the least screentime, having so far only appeared in The Avengers, Age of Ultron plus a cameo in Thor. As such, it would have been great to see him in Captain America: The Winter Soldier, as was the plan before the scene was cut, due to conflicts with Jeremy Renner’s schedule.
The idea was that Hawkeye and Cap would duke it out, once Steve is a fugitive from S.H.I.E.L.D., in what would surely have been a standout sequence of the film. Ultimately, it would be revealed that Hawkeye is only fighting Cap for appearances, and quietly slips him some info on S.H.I.E.L.D.
Seeing as they are on the same team in the upcoming Civil War, this would have been a nice foreshadowing of the pair standing side by side, as well as setting up the idea of superheroes going against each other.