Hmm yeah juhani would have to be replaced but with the Driods, i thought of an idea the story could have a big split point at it were you would have a choice to folow carth and help the republic or to follow bastila and try to find revan it sounds pretty cool, plus we might get mandolore i think 4 returning characters are enough dont you think? I say this because i would want to see more new npcs, also note that these characters might look quite a bit different from age and probbaly because of a new grafics engine.