I'd like to see touch pads continued; I like how the iPhone is used without a stylus, for example. There wouldn't be a need for d-pads anymore, which seem clunkier as time goes by.
Trackballs I'm not so sure of; the continuous movement that a stick can be provided simply by holding it down can only be replicated with a trackball by repeated twisting. It offers more precision on small movements, but it's convenient for longer ones.