"Take a look at The Old Republic and how it's handling things. Party members have the ability to select a dialog option to advise the leader, but it's the party leader who makes the choice on exactly what to say."
That's incorrect. Everyone in the party chooses a response, then the game randomly picks who's to run with. You get the light / dark side points dependant on your choice no matter what, but the response is picked from the pool of choices at random.
At least that's what the girl from Bioware told me in line at PAX.