We get some possible long term plans for Marvel Studios as it's being said that one possibility down the line is that if Robert Downey Jr. doesn't return, Marvel might be going with the "New Avengers."
Unleash The Fanboy has it from a source at Disney that "New Avengers" is a possibility, though it's noted it is incredibly early in the process.
The rumor could hold some merit as previously, I believe, both Kevin Feige and Josh Whedon have hinted their Avengers would feature a revolving line-up.
We could also speculate that it's also possible Marvel Studios could be going with "New Avengers" in Phase 4 following the departure of Robert Downey Jr. from the Iron Man role with a new actor coming on board. Feige has made it quite clear that they would not go with a reboot, but just have a new actor in the role of Tony Stark - similar to James Bond.
In the comics, New Avengers is a spinoff of the core Avengers group (maybe Marvel Studios would do the same and have two Avengers movie franchises?). While the comic book team consists of members that are a part of different movie studios (Spider-Man and Wolverine), the New Avengers is made up of Iron Man, Captain America, Doctor Strange, Iron Fist, Black Panther, Bucky Barnes (Winter Soldier), Ronin (Hawkeye), Ms. Marvel, Spider-Woman and The Sentry.