It's pretty much a definite now. Brad Bird talks to IGN about the difficulties of making a super hero sequel in a world with nothing but super hero sequels (looking at you Marvel). But the Incredibles was so good I think it deserves a sequel. More so than Cars... and Cars 2...
A lot of superhero films have been made since Incredibles and it is kind of like an athletic field that’s just kind of dried up dirt now, with a few clumps of grass. And I think what the challenge is how do you step outside of that and say, ‘Hey, there’s another place for our heroes to go.’ So that’s kind of the challenge.” “People make a lot of following some kind of road map and Damon [Lindelof] and I can tell you from making [Tomorrowland] that you’re just bumping into furniture. Hopefully if you’re on the right path you don’t actually know where you’re going completely. I love those characters in Incredibles, but I’m also a moviegoer and I want to be surprised by movies. I want them to zig when they should be zagging.