I was able to enjoy it as a stand-alone movie. I know a lot of people are saying "What about the other Avengers? What about Shield?" I thought about it, but it didn't bother me that much. I wanted to see how Tony was going to use his wits to handle this seemingly unbeatable bad guy.
I think this will be a problem for all future Marvel movies. The Avengers set the bar sooo high, that expectations are crazy.
Would you want *your* name attached to a potential bomb and then end up having almost nothing to do with the portrayal of your character? If they did it like the CGI Hulk there'd be almost nothing for him to do except voice-over.