To me, a better story for an Avengers single player game would've been Ultron, Kang, or something along those lines. Not Kamalia Khan coming in as a Jubilee type character and dealing with creating a bunch of Inhumans. Is that what anyone thinks when they think of Avengers? Felt more like an X-Men type of plot (super powered people being hunted and experimented on, a young hero being a kid sidekick, etc).
Imagine Ultron or Kang invading NY or LA and you get to explore one of those cities in an open world as the Avengers, or maybe a global threat with a "multi-region" type of map to explore.