Myself I'd rather give Larian the freedom to customize monsters if they need to. For instance, the canonical green hag was designed more for roleplay encounters than battle, so she's fairly weak, and makes for a poor boss villain. Also, like previously said, intellect devourers are supposed to have an instant-kill combat ability, so even 1 of them is a walking would-be TPK for newbie players. And do we really want Us to be able to insta-kill commander Zhalk and take over his body in the tutorial? What about canon imps' immunity to damage from Scorching Ray and Poison Spray? So yeah, I try not to be too harsh on Larian for things like that.
