Stark almost appeared in the scene when Steve Rogers, Wanda Maximoff, Vision, Black Widow, and Falcon meet up at the Avengers' home base. Joe Russo said it would have been a much different scene if Stark were there instead of James Rhodes to greet them.
"If Tony and Steve had to see each other for the first time, it would be much more complicated," Russo said.
"Which is why we didn't do it," McFeely added. "We tried in a few drafts, and it ground things to a halt."
The last time Stark and Rogers saw each other, Stark learned that Rogers' best friend, Bucky, killed his parents and that Rogers knew the entire time. They're not exactly on speaking terms.
The crew members pointed out that despite Rhodes' getting seriously injured by Vision and having every reason to not want to help them, his sense of responsibility to the world at large allowed him to put aside his personal feelings.
"Rhodey is once removed from that conflict," Russo said. "He's also an extremely heroic character, a military man, and understands that his sacrifice needs to be put aside for the greater good of the universe."