My big question about Karlach is: how did she end up this way? She was planned as a companion since pretty early on. They were certain enough about her that she got featured in the MtG set with the other companions. She's not like Halsin, who at least has the excuse of not being planned as a recruitable companion originally. Throughout most of EA they had her in mind, they were tweaking her look, but her actual questline... isn't really a questline. You just gather a couple pieces of metal and give it to someone. Compare that to Shadowheart and Lae'zel, even Astarion and Wyll.