The lich quest is one of two that can only be completed if you actually promote a character (the other is the priest quest). Leaving aside the XP you get for doing the quest, promoting the scholar fully results in a simply enormous increase in his potential power, not only from his being able to GM some combat-related skills, but also from the acclerated promotion that results from his being able to GM Learning. A fully-developed lich is a hugely powerful character.IIRC you're right, there is a bug with the Monster ID skill. I don't know about shield bash, though.
