I don't understand the hate for this one. The fact that Tony Stark is barely in the suit makes for an interesting take on analyzing the humanity of the character. I also found the villain plot twist halfway through the movie to be quite clever and surprisingly satisfying.
It certainly feels more like a Shane Black movie than an Iron Man movie, but that's a great thing. It shows Marvel is willing to give their filmmakers a voice and the room to take risks in their storytelling. Iron Man 3 is a very risky movie, and to me it paid off.