It's been less than a week since The Avengers: Age of Ultron opened in theaters and Marvel is already revving the engine on its next big superhero team-up. The studio announced today that principal photography has begun on Captain America: Civil War while detailing the main cast for the movie, and I'm just going to say it: things are starting to feel a little unwieldy. Obviously, Chris Evans' Captain America is starring in the film, but according to Marvel's announcement no less than seven other existing Avengers will also be showing up:

• Iron Man (Robert Downey Jr.)
• Black Widow (Scarlett Johansson)
• Hawkeye (Jeremy Renner)
• Falcon (Anthony Mackie)
• War Machine (Don Cheadle)
• The Vision (Paul Bettany)
• Scarlet Witch (Elizabeth Olsen)

On top of that, the movie is also going to feature Paul Rudd's Ant-Man, a character that audiences won't even formally meet until this July. But while that may seem like a lot, I can hear what you're saying right now. "Hey Bryan, it's not any worse than Age of Ultron. They don't even have Bruce Banner or Thor listed!"

But wait, there's more.

The movie is also going to feature Black Panther (Chadwick Boseman), Agent 13 (Emily VanCamp), Crossbones (Frank Grillo), the return of William Hurt as General Thunderbolt Ross, and both Daniel Brühl (The Fifth Estate) and Martin Freeman (Sherlock and far too many other wonderful things to count) in unnamed roles.

All of which is to say that Captain America: Civil War is starting to look like the most jam-packed movie in Marvel's history — and that's not necessarily a good thing. Managing an expanded universe like this is difficult because there are so many characters to keep straight. When you take your time and do so deliberately, you get the first Avengers: a wonderful pay-off filled with delightful character moments and action that becomes a global phenomenon. When things get rushed — or too much setup gets jammed in at the expense of the movie at hand — you get something a lot closer to Age of Ultron. It's also worth noting that while the original Avengers served as a capper to the first phase of Marvel's Cinematic Universe, setting up Iron Man 3 and every film that followed, Age of Ultron was a stand-alone movie of the week in comparison, leaving Tony Stark's angst and Captain America's disillusionment behind without barely a mention. If anything, it appears that Civil War has been designed to be the inflection point from which all future Marvel movies extend. As Yahoo's Jordan Zakarin put it, this is more Avengers 2.5 than Captain America 3.

That's not to say it can't be pulled off. Civil War writers Christopher Markus and Stephen McFeely proved that the Marvel universe could be something much richer with Captain America: Winter Soldier, and with the Russo brothers behind the camera there's every indication a film about internal strife amongst The Avengers is in the perfect hands. But we're also at a moment where the signs of superhero fatigue may be starting to appear. Age of Ultron is doing extraordinarily well, but nobody's saying it was better than the first. Ant-Man is just around the corner, but it hasn't picked up Guardians of the Galaxy levels of anticipation just yet. And every single day audiences are bombarded by more pictures of Deadpool, or the Joker, or Harley Quinn, or some other comic book hero being brought to the big or small screen. And that's not to mention the two Avengers: Infinity War films, which ostensibly will be even bigger than Civil War.

The benefit of an expanded universe is the opportunity to tell rich stories with a broad palette of characters over the course of years, not hours. The danger is audience burnout.

Verge Video: The entirety of Marvel's Cinematic Universe