naw, it's an interesting idea i guess, but there are many people who want a new playable character, as opposed to exile and/or revan again.
The idea about how they would be different plot-lines is good, since many successful novels switch between plot-lines like that, and i am sure there could be many options upon confrontation, if you have none, one, the other, or both characters be DS.
One tip for inserting ideas, is to space your post with paragraphs, since it seems easier to the brain to finish a small segment and be done, like a checkpoint.
Anyway, welcome to the forums i guess.