This article includes informed speculation that could be spoilery for Avengers: Age of Ultron and beyond. Be warned.
Kevin Feige is proud of Marvel Studios' track record. When I interviewed him for Captain America: The Winter Soldier he boasted that the seven year course he and his planning committee had plotted before the first Iron Man had worked out more or less as they saw it. They've recently gotten together and plotted out more years in advance, leading Marvel well into Phase Four - they have an outline for up to 2028. That outline is subject to change - I bet they had an Incredible Hulk 2 slotted in to Phase Two at some point - but it gives the broad strokes of where they want to go.
And according to Disney's Bob Iger some of where they want to go is spin-offs. The studio built itself up by bringing disparate franchises together into The Avengers, but now they want to take the team created in The Avengers and spin off solo movies.
Iger and Alan Horn, chairman of Walt Disney Studios, recently met with the Marvel team to talk about new heroes who will be introduced in Age of Ultron and could be spun off in their own films as well. Iger declines to name them. “The possibilities are endless,” he says.
Well, they're not 'endless' if we're talking about The Avengers: Age of Ultron. They're pretty small, actually, and I am pretty sure they really boil down to "Ms. Marvel." I guess it could Quicksilver or The Scarlet Witch, or it could be Vision, but I think it's going to be Ms. Marvel. I'm really betting on it being Ms. Marvel. At this point I think they'd be crazy to not go with that character, and everything I have heard leads me to believe she'll show up in Ultron, even if just as a cameo.
They may want to do spin-offs with The Guardians of the Galaxy as well:
Iger would like to replicate the success of The Avengers with other Marvel teams. He says Marvel could potentially spin off members of the Guardians of the Galaxy, which include Star-Lord, Gamora, Drax, Groot, and Rocket Raccoon, in their own features.
I don't know if I believe that so much, but could I see some members of the Guardians splintering off and hanging out with Hulk in space in a Planet Hulk movie? Why yes, I could. And I don't think that's so far-fetched at all, despite Marvel's previous denials.
All of this also makes me wonder about Black Panther. What if I told you that Age of Ultron invokes Wakanda as Ultron gets his comic book famous vibranium shell?