I mean to each his own but IM2, IM3, AOU and Thor 2 are fukking awful.
Iron Man 2 was really Iron Man 1.5. It literally picked up where the last one left off. It introduced Black Widow and got fans acclimated to the new Rhodey. It wasn't bad. I think it was more or less made to be mostly filler.
Iron Man 3 was pure filler. At that point Iron Man was marvels biggest draw so they had to do another sequel. It should've been called Tony Stark instead of Iron Man 3 though.
AOU should've been a 2 part movie and based on Whedon's comments, there was enough to the story to justify a part 2. Whedon struggled with trying to juggle that many characters in a movie... HOWEVER, Whedon's fumble allowed the Russo Bro's to pick up to rock and return it for a TD with Civil War.
Thor 2 was ruined by the forced romance. It was the first time that Marvel tried to shoehorn/force a character (Jane Foster and her sidekick) that didn't really fit. Thor had way more chemistry was Siff and Valkarie.
Marvel isn't perfect but they know how to adapt and learn from their mistakes. They're also not afraid to take risks.