I absoluley love Kira, but unfortunatley, she takes very little aggro. Im not saying replace her, im saying increase her threat generation a bit.
she's a melee dps character, she's supposed to do very little threat. thats like her job lol. plus she's extremely important tot he story lol.
anyhow back on topic. i'd say the following....
Rusk from the JK. he just sorta joins you for no real reason. plus he's so stiff and not really likable at all.
Bowdaar from the smuggler - he's pretty damn pointless. he's a mopey whiney wookiee. he's got no real personaltiy aside from "hey im a wookiee and im gonna complain about being a slave once".
Iresso from the consular - same thing as rusk, except he's alot more likable as a character.
i'll probably get alot of hate for this one, but i'm going to say Khem Val from the inquisitor. yeah he's story relevent and stuff. it just ALWAYS bugged me why the hell my inquisitor would keep this big Dashade monster around when he CONSTANTLY reminds you how he wants to kill you. why would you do that? makes no sense. (my favorite inquisitor companion oddly enough was ashara, the one most inquisitors complain about lol)