Ultron would be amazing for 3.0. I'm interested to see where Star Wars goes (Original, Rebels and VII?).
If I could choose a couple of characters for 3.0, I won't mind seeing the Emotions from Inside Out, Ant-Man, Daredevil, the rest of the Big Hero 6, King Candy/Turbo, Fix-It Felix, Robin Hood, Kuzco, Kronk, Yzma & Patcha. :3