Well... Haven't been around here for a while, but recently picked up TSL dirt-cheap. (Almost finished it, so if I have anything that conflicts slightly with it, that's why) The working title for this would be Kotor III: Amnesiacs Anonymous.
Basically, you'd start off a couple years after TSL. An era of peace and prosperity will have returned, with the Republic now stronger than before and flourishing. The Jedi Council will have been reforrmed, and the Jedi themselves, though few in number, will be growing, with somewhat unchecked abandon as they try to regrow their numbers. (This will obviously be a change from the previous two games where the whole galactic system is in danger at the start.) The opening crawl would go on to mention a jedi now entering the edges of known space, back from a long mission and armed with knowledge that could save the Order and the Republic.
The opening scene would have you start out in a severely damaged Shuttlecraft, which would be recovered by a Republic Cruiser. After several scenes detailing medical treatment to pull you back from the edge of death, you would wake up, floating in a tank of kolto, and facing some questions from the Captain.
Basically, you would remember nothing- your name would be given to you from a fingerprint and retinal scan they pulled on you. So the knowledge to save the Republic would be a trifle dicey to remember, at best.
Obviously, you would be playing as Revan again, reconnecting with old members of the team, trying to figure out what it was you'd forgotten. (you'd remember little flashes, again, but nothing even so coherent as the Star Maps.) Once again, you'd have to go out, retracing the steps, with old party members and new ones.
So, basic idea there of starting the whole business.
Quoth the Raven; "Nevermore, nevermore."