In an interview with MTV, Marvel Studios President Kevin Feige dropped a rather interesting comment that has led to some rather interesting speculation. In regards to Avengers 2, Feige said, “It's still early days, but I told [Whedon] after reading the first sketch outline he delivered — and there's a lot of work still to do, he has to sit down and turn this into a movie — but there are already seven things in there that are worth the price of admission alone.”
While Feige wouldn’t reveal the seven things of course, the natural speculation is that he could be talking about seven team members. The first Avenger team had six team members, so adding a seventh member would make sense. Because Joss Whedon has indicated that he would like to see more females in the Avengers, The Wasp seems like the most likely candidate to become a seventh team member.
However, there’s also no guarantee that all of the original six team members will be back. While it’s pretty likely that Iron Man, Thor, Hulk, and Captain America will return, Black Widow and Hawkeye might be deemed expendable. Black Widow likely has a better shot at returning than Hawkeye, since Whedon wants to keep the female count up.
If Hawkeye gets booted or regulated to a minor role, then the next question is who would replace him. One likely candidate could be Ant-Man, since a solo Ant-Man movie is set to be released on November 6, 2015. Disney might decide that Avengers 2 is the perfect place to introduce Ant-Man and build momentum for the Ant-Man movie. However, Disney also might want to save Ant-Man for his solo movie. Our guess is that Ant-Man gets an after-the-credits appearance to tease his solo movie, but Disney will want to save the bulk of his introduction and origin story for his solo movie.
So after Ant-Man, who would we expect to see join The Avengers? Our bet is both the Falcon and Black Panther could be likely candidates, as they would also bring some more diversity to The Avengers. Falcon gets introduced in Captain America: The Winter Soldier so he could be worked in without having to include an origin story or explanation of who he is. On the other hand, there have been lots of rumors involving Black Panther, so Avengers 2 might be where the character first shows up. Adewale Akinnuoye-Agbaje has also hinted at talking to Marvel Studios about playing another Marvel character in addition to his role in Thor 2, and he's been a longtime fan favorite for the Black Panther role.