Karlach, Halsin, Jaheira, and Minsc should never have been companions IMO. There just wasn't enough time to flesh them out before launch (they were all initially intended to be just quest NPCs). I applaud Larian for trying, but I feel it was a bit too ambitious.
Let's hope they continue to work on them (and Wyll) for the Definitive Edition.
Unlike those other 3 Halsin wasn't a planned to be a companion from the start, also he's redundant AF, we lost our Halfling Werewolf Bard companion because of him, he's only here as companion because of popular demand.
