Revan & the Exile disappearing into the Unknown Regions was originally just a way to get rid of a powerful character to make way for new characters in sequels.
It doesn't make sense for Revan to go into the Unknown Regions alone, at any rate, if he got seemingly subjugated by the Sith Empire years before. What would make sense is Revan staying behind and becoming some kind of war leader of the Republic in preparation of the coming war.
Giving Revan a role similar to Conan in Age of Conan would've worked out.