You're giving Larian too much credit for the other companion quests in my opinion. No one got a truly decent ending except SH and Lae'Zel. Yet, Karlach got the shortest stick available.
There is an overarching problem that even scretches into the conclusion of the main story. It's fair to say Larian was doing their best to give players the impression that they can't write endings for the life of them. I genuinely think this game is missing a whole year of development. It's affecting everything near the backend and particularly internal consistency. It's riddled with bugs and systems that needed failsafes. Much of it is unfinished, unpolished, untested and unbalanced.
