it depends on how you like Whedonspeak which this film certainly had and which i certainly enjoyed
X-Men: First Class had the same problem of sacrificing character development for the supporting cast in favor of their two leads (which were the only real high marks of the movie!) but it was more glaring because of how strong McAvoy and Fassbender were in their roles and the lack of ANY memorable moments from the entire "first class!"
Cap, Hulk, and Thor also had the luxury of having their own movies to be fleshed out character-wise so the people who watched their solo movies already cares about them by this movie
while McAvoy and Fassbender did bring the emotional weight to their roles, everything else about First Class was lightweight especially the SFX, the production value, and action scenes compared to the Avengers which was just a marvel to behold!
--
all you need