There's never going to be room in Avengers to give a character a full backstory. They're always going to need to be cut, and the person who we have no investment in is always the best option to cut, right? If you give them a supporting cast part in a solo film (or two) you can expand on them with relatively little screen time in Avengers, you get the full character with all the gravitas, cool dialogue moments and emotional climactic payoff, without needing to spend a team up film trying to develop them and inevitably failing. His role was fine, no doubt, but it could have been better, maybe even great if he had been Coulson's go-to guy during Thor. Now, it's possible that that was the plan and Renner just wasn't available, if indeed his scene was clearly shot after the rest. If so, too bad. Still, not something I'd want to see from my fave Avenger. I would not enjoy the movie as much, just like I didn't enjoy the X-Men films. "They films are about Wolverine" does nothing to my deeprooted expectation that superhero team movies should be about the whole team. Same with Avengers.