If this thread is just supposed to specifically be about a possible confrontation between the Exile and Revan, then it is a interesting idea. If it is just a general idea that you thought of and isn't supposed to be specifically about your idea, then there is already a thread for this- KotOR III Story Ideas (
http://lucasforums.com/showthread.php?t=150731).
I think that this is a good idea, it would be nice to see Revan and the Exile meet up again and have a confrontation, maybe even if you set them both to lightside. Of course, you could make on dark and one light and they would fight each other, or both dark and the Exile might become Revan's apprentice or they would fight for power. There are a lot of possibilities.