Well, my wishlist includes the following:
(Personally, I'm pretty happy with the characters we have already)
Deadpool (You KNOW he would be a fun character to play with. Disney would probably have to negotiate with FOX to get him in, though...same goes for the other X-Men)
Winnie-the-Pooh, Tigger, and (for a third Pooh character) either Piglet or Eeyore (You could probably infer that from my username.
I'm surprised that they haven't become characters in the game already. They're already toys for Pete's sake!)
Hercules (I'd say he's probably a shoo-in for 4.0, though.)
Mushu (because Mushu, that's why)The Emperor's New Groove
Play Set with Kuzco, Pacha, and Kronk as playable characters.Atlantis: The Lost Empire
Play Set with Milo, Kida, Vinnie, and Audrey as playable characters.
Ferb, Dr. Doof, and/or Candace (We at least need Ferb, anyway, but playing as Doof with his Inators would be awesome.)Gravity Falls
characters (Dipper, Mabel, Grunkle Stan, and maybe even Soos or Wendy)Wander Over Yonder
characters (Wander, Sylvia, and Lord Hater as playable characters)
Kim Possible (perhaps they could include Ron Stoppable as well?)Recess
characters (This might be a long shot, though.)
Chip and Dale (as they appear in Rescue Rangers
characters (hey, if they can work Cars characters in, surely they could work fish in. It's a good time to do so, too, with Finding Dory
coming out soon. As far as characters would go, I'd say Nemo, Dory, a Tank Gang character (either Gil, Bloat, or Jacques would be my best guess), and one or two characters to represent Finding Dory
(probably the new characters Bailey and Destiny if they aren't considered too big, but hey, everyone's a toy!).)Up
characters (Carl and Russel. It wouldn't surprise me if they were saving them for 4.0, though, if they're not among the rumored unannounced 3.0 characters)
Elliot (Pete's Dragon
) (They have a good excuse to put him in at this point, given that the movie's remake is coming out this year. He could be too big, on the other hand.)
Ben Gates and Riley Poole (National Treasure
) (They lend themselves pretty well to being Toy Box characters, at least. (And it would become possible to play as Nicolas Cage.