I would not mind having a very mean and very stupid companion. A goblin maybe, or a troll or an ogre. Someone without a troubled past that needs resolving. Someone who only cares about her/himself and who will spoil your plans and deceive you in the name of short-sighted self-interest. I think someone like that would make a very intersting companion.
Korgan and Kagain could plausibly still be around! Two evil dwarven mercenaries that would fit that bill well. (and BG III could use some short companions too IMO)
