Kaliyo is a bit of a strange tank, far too rogue-ish to be a punching bag, I agree with Vector being a more realistic tank.
In fact none of the healing companions make sense with the exception of Doctor Lokin for the IA and Doc for the JK. Otherwise it just seems that BioWare have made the dorkiest companion of each group the healer by default lol.
Mako isn't the dorkiest.
I still think they screwed up PCs! My Agent uses a blaster pistol in every cutscene, but I can't use one in game? o.O