I don't think it was the lack of amount of action, but how I felt that the action itself didn't feel as intense as it could be. I mean the shoot out sequence in the Hellcarrier between Fury and Loki's henchman was a prime example in my honest opinion of how "tamed" the action was at times. There was really nothing exciting about the way that sequence was shot, and while it was a dream to see the Hulk and Thor go at it, that too felt like it was tamed and the cinematography didn't feel inspiring at times either. Plus, I felt like the intensity and full power of Thor's swings were more evident in his solo film than they were in the final battle of New York. I just think that this boils down to how Whedon didn't have as much experience in handling large scale action sequences at the time that he had shot the film.