I'd love to see Kida from Atlantis as a figure, but I'm sure sure how great Milo could be. I'm iffy on him, but they would make a nice Toy Box pack. Quasimodo and Esmeralda from The Hunchback of Notre Dame would also be amazing Disney Infinity figures.
However, I'm not sure either of those movies/characters are very popular beyond big Disney fans. But I would love to have them!
My wish list for more characters in 3.0 would be: Oswald, Goofy, Pocahontas, Kristoff & Hans (a Frozen play set), Flynn Rider, Flik & Atta (A Bug's Life play set), Remy & Emile (a Ratatouille play set), Fix-It Felix & Sargent Calhoun (a Wreck-It Ralph play set), Vidia, and Mushu.
I'm pretty sure Emperor Palpatine and a Boba Fett will be included for a Classic Star Wars, and of course there will be characters for Star Wars VII: The Force Awakens...