It seems likely that there's going to be a major update to the game that adds the new SW set and probably a few figures they're planning on releasing later on (like Peter Pan and whoever they pull from the Fan Poll). I think it's possible we see a new set for Jungle Book or maybe Alice in Wonderland since there's new live action movies coming out for both of those. But if they decide to do that, we're probably not going to find out about it for a while.
Personally I'd really like to see another Toy Box Expansion game, maybe one based more around platforming and puzzle solving to complete the trifecta of DI content types (combat, racing, platforming) where every character can be part of it. But that's probably unlikely since the Inside Out set is kind of covering that.
I agree with you; if we are getting more playsets, they will be based off of Disney Live-Action films.
I also agree that we should get another Toy Box Expansion, with it spanning levels across all the four branches (Disney, Pixar, Marvel, Star Wars). It could have 20-30 levels each based off an IP:
-Mickey & Friends (Old-School Steamboat Willy Level)
-Frozen (Elza's Ice Castle)
-Tangled
-Gravity Falls (A lot could be pulled from this)
-Phinas and Ferb
-Aladdin
-Nightmare Before Christmas
-Tron Legacy
-Toy Story
-Monsters Inc.
-Incredibles
-Inside Out
-Brave
-WALL-E
-Up
-Bugs Life
-Spider-Man
-Avengers Adventure (3-5 Levels)
-Guardians of the Galaxy (2-3 Levels)
-SW Clone Wars (3 Levels)
-SW Original Trilogy (3 Levels)
-Episode VII (2 Levels)
Seems like a lot to pull some great levels from. Plus the fact that they could use assets from the Toy Box/Playsets.