For movie 14, I'd like to see Chomper, Ruby and Shorty come back. Chomper and Ruby were really great characters to have along with the gang and introduced new dynamics in the group. I'd be interesting in seeing how Shorty's relationship with the gang develops, in particular with Littlefoot as his foster brother. I also kind of want to see Pat again: he hasn't been seen since the end of 10 even though he's living in the Great Valley, and I'm curious to see whats happened to him.
If they make more sequels, I'd like to see Chomper and Ruby become regular or semi-regular parts of the cast, but I wouldn't want the main cast to get larger than seven, otherwise, there could be too many characters. Still, I'd like to see some returning appearances from past sequel characters, in particular Shorty, Ali (I'd personally like to see the two of them interact), Mo, Guido and Pterano. I know they're in the Great Valley right now, but I'd also like to see more of Tricia and Mr. Thicknose as well.