The audience at my theatre groaned at the end. I totally agree with you that the movie isn't as clever as it wants to be. I know some people who were fascinated by the movie, but I felt it had mistaken complicated for complex. I didn't feel like I got enough insight into Cobb's character to justify him as the focus for the movie, and since the action sequences all took place within dreams they seemed like time-fillers with no consequences (until they threw in the "limbo" bit but too little too late).