Jon Favreau should be very proud. I can't think of anything I would change. Perfect casting, perfect length, perfect story. And the sequel tease didn't annoy. It just got me excited for the sequel.
I'm so happy Robert Downey Jr was able to return from his troubled times and come back out on top. I've been a fan for so long though I think Heart and Souls is my fave. He was Tony Stark. Great casting.
And Gwyneth did the best thing for her career when she went away for a couple years. I've now forgotten what grated about her and enjoyed her performance.