Re: Avengers Sequel ideas?
... wouldn't Ultron be the villain for an Ant-Man film?
Anyway, I figure by then they'll include at least a couple of the following: Ant-Man, Wasp, Dr. Strange, Black Panther, Luke Cage and Ms. Marvel
If they find some other good villain for Ant-Man somewhere, great, otherwise, Ms. Marvel may lead well into an alien invasion by the Kree. Otherwise, Kang would make a great event villain.