It would be nice to be able to make NPCs with Player Models a la Mirror Image or something to the effect. I have a phase where I have multiple characters that are a part of the story. It would be cool to be able to have one physically represented even while I'm playing the other. Also, it seems like a really awesome way to make very phase-specific NPCs.
Bonus suggestion: being able to select gobs by name for when there's too many around to single out the one you want.