2. Go Big Or Go Bigger
In order to keep audiences interested, sequels are usually touted as being bigger and with higher stakes. How many commercials have you seen with the tagline being "Character X faces his/her biggest challenge yet..."? Marvel has averted this problem so far by keeping the antagonists of each film specific to a particular character's backstory. But after the world has been placed in danger in each of the films (and after The Avengers destroyed most of New York City), they've run out of real estate to threaten. Marvel has decided to go big in other ways, by introducing more and more characters into the fold and by making the universe even more sprawling and unwieldy. This makes sense in a way, if each team-up includes new members the dynamic will change slightly and there will potentially be more tension to exploit. However, after a certain point, too many protagonists means the same thing as too many villains, and Spiderman 3 proves that there is definitely such a thing as too many villains. This ties back to Sony's plan to have a movie based on the Sinister Six, it's like they haven't even watched the movies they just rebooted. Having the Avengers team up in comic books allows their respective storylines to ebb and flow over the course of several issues, putting all of that together in Avengers 3 and beyond is going to be exceedingly difficult. Having an expanded universe also throws a wrench into any individual storyline, as in "Why didn't Tony just call Bruce Banner to get him to punch Aldrich Killian in the face?" If each stand-alone story is supposed to carry the same weight as the team-ups, why don't they always team up for their big adventures? It's a question that has been plaguing comic books for years, and the absence of this idea is also largely what made Christopher Nolan's Dark Knight series so fresh. If this seems nit-picky it's because it is, but when everyone picks at the same scab it's only going to get worse. The casual movie-goer is going to think that Captain America could really use a helping hand from a certain billionaire playboy philanthropist until he finds the strength to save the day all by himself. Making the movies stakes high from the get-go means that Marvel has backed itself into a creative corner.