Kevin Feige On Hulk:
[Hulk] is going to appear in many of the movies announced today. Part of the fun of Avengers: Age of Ultron was saying, ‘you’ve seen another Iron Man adventure, you see another Thor adventure and another Cap adventure, but we haven’t seen the Green Goliath again. So that was important in the characters you haven’t seen – Hulk being one of them and Hawkeye being one of them – Ultron will make up for it.
On Black Widow:
Black Widow couldn't be more important as an Avenger, but like Hulk the Avengers films will be the films where they play a primary role. [Her role] is very, very big and further develops her character. The plans we have for her through the rest of the Avengers saga are very big and she is a linchpin. So instead of taking her out there or doing a prequel which we haven’t done yet, we’re continuing the forward momentum of the continuity of the Cinematic Universe, of which Widow is a key part.