Iron Man 2

Marvel Studios gave you exactly what you wanted. You wanted a movie franchise that tied into something larger, in this case, The Avengers. In that respect, Iron Man 2 was a wonderful film. In comparison to other non-superhero or comic book movies, maybe it wasn't the best, certainly not as good as the first Iron Man to be sure.
There were probably too many characters to keep track of, and probably too many plot points as well. But it worked. Why? Because its the first for reals attempt at a comic book movie.
I always appreciated Ang Lee's Hulk for it's action-in-frames approach. He wanted to make it feel like you were watching a comic book come to life. But I think he missed the point. The frames aren't really the secret sauce of why we like comic books or why we like movies made from comic books. That secret sauce is pretty simple: dangling plot threads.
I stopped reading comics regularly after Civil War for the simple reason that the need to constantly leave the story open ended just left me frustrated. The best comics wrap themselves up after they tell their story, then they move on. But the stakes that were set in forth with Civil War were immediately undone by whatever the fuck the next event was. They needed to set up the next thing, thus giving valuable plotting to a story we didn't really give a shit about. "Oh guys, Hulk is coming back. That should be fun." Turns out, nowhere near as fun as Civil War.
Iron Man 2 gave us exactly what we asked for. It established the universe in which future Marvel movies will be set, and as a result had an ultimately underwhelming climax that removed the stakes, in an effort to leave enough room as possible to establish the next story. In essence, it did exactly what Marvel comics have been doing for decades.