Honestly a lot of my speculation is WoW faction war era writing trauma, where a lot of story content got cut/reworked to fit new narratives to try to make the story more palatable to players, coupled with the Persona series making me keenly aware that there are different social dynamics regarding family in Japan (having illegitimate children apparently destroys your reputation there.) Aside from that though, Zoraal Ja just doesn't click as a villain. The first half sets him up as this guy whose actions don't really reflect what he says; He spares Bakool Ja Ja, he clears the road for people, and he helps against Valigarmanda. The worst he ever does to you is something that Thancred does in the previous dungeon on purpose. He basically has to develop himself from being a non-entity to the main antagonistic force over the course of 1 and a half zones. Not to mention the one-two punch that completely shattered my suspension of disbelief being the Ketenramm situation:
-Ketenramm is ambushed and clearly slashed (by Zoraal Ja.)
-Zoraal Ja proceeds to kill his advisor and does an evil laugh in complete contrast to how he behaved before this point. (OK, this is a mask off situation and he's going to revel in his villainy from this point onwards.)
-Ketenramm is alive in the next scene you see him and is literally no worse for wear. He also has absolutely no story relevance for the rest of the plot so he may as well have died. (I got too distracted by the fact that he was still alive to really take in Gulool Ja Ja's death)
-Zoraal Ja is back to being his stoic self with his rage boiling over at points. No consistency with his evil laugh, he never does that again.
The inconsistency feels as bad as the Warriors of Darkness where they're clearly reveling in the harm they cause before they pull out their sob story, only that the visual storytelling is trying to make us feel sympathy for them after that fact. You could speculate that they're trying to act out a different persona to disassociate themselves from what they're doing but that's still just speculation.