Number 16: Iron Man 2
Iron Man 2 swapped Terrence Howard for Don Cheadle and brought War Machine to the party. The Iron Man sequel had to do a lot of universe building for the MCU as a whole while further exploring Iron Man’s role. That didn’t always work as smoothly and in some instances, the greater MCU references felt forced. On the plus side, Agent Coulson, Nick Fury and SHIELD had a more significant presence and Scarlett Johansson had an impressive debut as Black Widow.
There was an added emphasis on humor, which undercut some of the drama. That definitely didn’t help Mickey Rourke, who was essentially playing two villains — Whiplash and the Crimson Dynamo. In hindsight, Marvel Studios would have been better suited making Whiplash a separate character and let Iron Man and War Machine take down Rourke’s Crimson Dynamo in the final act.