I doubt either side would want Vader present. The Rebels wouldn't, because they would experience the unpleasantries that the NPCs of the PT game have been experiencing all along, in regards to lightsabers and Force powers, and the Imperials wouldn't, because he would probably strangle a few people for their mistakes.
Ush, does the Wookiee bowcaster still have its +1 charging ability? Arvus would like to use a bowcaster, and I was unsure if that +1 was still present. Still a useful weapon, though.
I would love to see how Vader deals with Senators, he seems to be to blunt for politics, propably decent general but bad in subtleties. -This is one reason he didn`t have as much power in Empire as he would like- second one that Sith Master never fully trusts the Apprentice.
He was just an Emperor`s Hound, assigned to do particular tasks, especially when Emperor wanted to keep his other servants in check.