As a fangirl I would like to have both Carth and Atton with me and have them fight it out
Seriously though it would depend I mean if you are the Exile again then it would be fitting a couple of your former party members but some new ones would be warranted i.e. GOTO has got to go and I wasn't all that fond of either Mira or Visas though they were useful at times and the more jedi the merrier.
If you are Revan then it's a bit odd because in TSL Carth pretty much says you didn't take anyone with you and we know he, Canderous and HK didn't go with Revan. So there is opportunity there for a range of new characters or perhaps you could mix the two groups. That would be interesting.
I wouldn't mind the option to play either Revan or the Exile and have it effect the party outcomes and other parts of the game.