I think that it is possible for him to start a new relationship, but it would be extremely hard to him to move on from his past.
If he indeed survived events on the Foundry, I think he would be in the same emotional state as Bruce Wayne in the beggining of The Dark Knight Rises. Man full of suffering, sense of loss and guilt. He is completely alone. Everyone he knew and loved are gone. I would like to see him find new life.
BioWare should focus more on his mental and emotional side, not only how cool or powerful he is.
You're right about that... but "everyone gone"? I'm still waiting for something like: Satele I'M YOUR GREAT GRAND FATHER-or something...just like when Luke met with Cade Skywalker. AND I understand that the TOR is about the new herose and all... but The KOTOR without Revan is like Episode IV-VI without Vader (Luke as the "new hero" just like Hero of Tython in the ToR and the others), or WoW without Arthas, and the TOR is the KOTOR3 even if u accept it or not. IT'S THE STORY ABOUT REVAN and the others who helped him... since not even Luke was able to do every thing alone!!!