In a previous patch Larian aknowledged that a murderhobo run granted more XP than a pacifist run, so they balanced it by giving more XP to quests if you avoid fights.
Also the level cap seems pretty low so you’ll probably hit it quickly if going completionist plus alternative solutions and then double dipping XP by killing anyway.
Have a feeling there may be severe reactivity consequences to murderhobery, and definitely some level of opportunity cost. I don’t think Larian LIKES to encourage murderhobery narratively.
