Re: Anthony Mackie in talks to play Falcon
I think you're over thinking it. It's still just a story at the end of the day. One that can only handle so many characters and a derivative superhero probably isn't the best addition to the team. War Machine could busy somewhere else or whatever they give in a tie in comic or not. Not every hero needs to be present in one location.
Again, I didn't see any major critique of the film not featuring WM and the story didn't collapse in on itself because of it. Clearly WM wasn't needed and it's not as big of a deal to not have explained that as a couple of fans on a message board might have you believe.
Logic would dictate that WM would have done something if he were present. However, he wasn't because he didn't feature in the film. The comic is a nice tie-in for fans and answers some questions some may have, but it's not exactly necessary when it comes down to it.