Sure. I wouldn't call Xu a main character, but it's not just the lines-the things she does, and the things she says (she does get more than five lines, and a lot of it is body language) does seem to me to at least present /a/ personality--though some of it's up to interpretation. And I like that, at least, what I see--especially since it's a good way that the game shows that people have relationships /outside/ the main party, since she's obviously a good friend to Quistis.