Oh my, sorry for the mass topic engagement mode I am in haha, I am a bit eager.
So well, the games might not be like several years between them but nonetheless, I was thinking of using the same method a site called "Face of the Future" uses. Google it. To morph your character's so that they look older. I couldn't, unfortunately, access the site myself so I couldn't see the quality. But I did an experiment of my own (using Photoshop) to make one guy (I know not his name) look older.
Original:
http://i8.photobucket.com/albums/a32/Damienz/M0001L.jpgOlder:
http://i8.photobucket.com/albums/a32/Damienz/M0001LOldv2.jpgEDIT The older picture was a quick-job also, just had to say it =P
In the Older one he is a bit more "concerned" due to hardships or whatnot he's been through (just for show really). But the core of the idea is, is it possible to make the game gradually change the picture as you go through the game? Another thing, in Wolfenstein-eque, could it be possible to make the portrait become more damaged the less health your character has? The thing I can think of is that you'd need lots and lots of portraits stored somewhere and the game would need to grab data from there and replace the portrait in-game actively. And I don't know if that could be possible.
I am also thinking, if your character would go either evil or good his facial expression would also change, although now I might be going into a bit of a major project thought pattern here but, just want to know what the limits are (what you can and what you can't do).
Thank you in beforehand,
Osvir