In the original, it was common for players everywhere to use the characters they became most efficient with, which meant that the Jedi Jolee, Juhani and Bastila were used more often than any other set of party members. Since they were Jedi, there was really no reason for keeping say, Mission or T3-M4 in your party when you could wield the power of these dominant companions unless you wanted the flavor or additional quests. In The Sith Lords, different companions may be off doing their own mission, thereby "allowing" you to utilize some of the other party members more often. It is said that each companion will have a uniquely helpful ability or trait and that missions will be designed to take advantage of these, encouraging diversification.​