Originally Posted by Crimson King
Black Widow and Hawkeye are not sidekicks. MCU War Machine and Falcon are pretty much the definition of one.
Planting Falcon in A2 now is to assume a huge popularity bump for that character, and they don't have a clue how much/little fans will like Mackie's performance. Seems like a risk that Marvel doesn't usually take. Hawkeye and Black Widow have more connection to the Avengers stories than War Machine and Falcon. They all have connections, of course, but BW and Hawkeye's are stronger. I don't really see it as the same thing.
In the 90's War Machine was with the Avengers West Coast & Force Works. With them in the Avengers/X-men crossover called "Bloodties" and some others.
Now the Falcon you have a point.