The first Iron Man lacked an overly engaging story for me to keep my attention or want to keep paying attention. Captain America the first one was really really really really dry. I saw it opening day all hyped up and then 30 minutes in I was just done. Iron Man 2 suffers from the lack of me even caring about any of the characters which is the same problem Avengers faced. Iron Man 3, I personally was just done of Iron Man. Avengers was more so explosion and action than story that keeps me engaged. Captain America 2 fixed the story being dry problem and it started out super strong but it just go boring towards the end.
I kinda wish Marvel did what Sony did when they rebooting X-men (From First class onwards) but I'm sure
@TeriofTerror was great in Cap2 and Avenger