Originally Posted by BMM
If you go into X-Men: Days of Future Past thinking that a character like Blink is going to receive the same amount of development as Charles Xavier, of whom there are two, you deserve to be let down. You don't go into The Dark Knight thinking Gordon is going to receive equal treatment as Batman or The Avengers thinking Maria Hill or Pepper Potts are going to receive equal treatment as Tony Stark. Same applies here.
On the other hand, Blink, Commissioner Gordon, Pepper Potts and Maria Hill are not major fan-favourite superheroes, so no one expects them to dominate. Gordon still managed a good slice of screentime though.
It's when big characters are given tiny roles that fans don't seem to like it.