as much as i'd love to have a sequel to the gameboy camera and have them revisit face-mapping modes in games like they wanted to try on n64 (see: perfect dark), i dont see it happening. sure a new camera could surface and there will be some camera-game interaction but as for face-mapping; i dont think it will fly.
the reason they said they cancelled it in PD was because of possible controversy. they used examples of kids mapping the faces of the prez or a school teacher or something into a game like PD and riddling them with bullets.
if that is the main reason, i dont see them changing now. that is why a caricature-making software included within the sytem is more reasonable. using different types of noses and eyes and mouths and matching them up to make a face is all it would take to keep nintendo safe from liabilty. the face mapping in the gb camera to perfect dark looked really good in the sole screenshot i've ever seen, and with the better tech available now a gb camera 2 or ds camera in conjunction with Wii's graphics would be even more believable. with the caricature software however, you'd have a face that LOOKS like yours or whom you choose to creat, and not a near perfect likeness, they could avoid people like jack thompson from saying "now these companies like nintendo are allowing our children to put the faces of their enemies in and letting them take 'pixel perfect' aim with what feels like a gun in their own hands."
its bound to happen with even the caricature software but i dont see it being as bad. you make a face that looks kinda like someone else and you can say its coincidence. you cant do that when you put out software/hardware that will let you upload a picture you take into the game and map that to a character.
sorry if any of this seemed random but i was reading something on jack thompson on ign and felt like ranting a bit.