Re: MCU Phase 3: Have it your way
I agree that the format of several individual character movies building up to an Avengers movie may get a little stale. But, I think you may be missing the bigger point.
The reason why the Avengers movies are the ones being built up to right now is because the Avengers are getting formed.
I think where Marvel is going to go with this is the movies each become more about the "story" and not the superhero. So, instead of a "spider-man" movie you get "Kraven's Last Hunt" or "Brand New Day". Instead of a Captain America movie you get "Destiny War".
Then, the big 2-3 year meta-tentpoles can be the big crossover stories like Secret Wars, Civil War, Skrull-Kree War, Identity Crisis.
Once they "create" the Universe and give it texture it becomes more about the stories in that Universe and multiple superheros can come and go as needed. New Marvel superhero characters can be introduced in the "stories" or in their own new movie where maybe it will be named after them. For example, Moon Knight.