Remorse? Regret? If you killed thousands of people, wouldn't you need some time to yourself? As for DS, more possibilities:
DS Male with love for Bastila: Someone went the betrayal route, killed Bastila, Revan went the vengaence route, blew up the Star Forge...and so forth...
DS female: Harder to explain...maybe just went soft, after seeing all those puppies and clothes on sale...
Maybe you are involved in those adventures, after all, the Force works in mysterious ways...
Actually, you couldn't have continues as Revan because they way the first was built, you know, couldn't continue saves...and if you want a new Revan, how plausible is that? Another mindwipe? That would ruin the story...and what do you have against DS?
No rehashing please...