Does the magic mace only do one damage when it hits? If so, then your assessment seems correct, i.e. he is better when he stays away from being adjacent to a monster. Of course, he may not always be ABLE to stay away from being adjacent to a monster.
Yes, his magic mace is Attack + 6, Damage 1. So the same amount but not an auto hit. Seems like he is a good Ally to have around. Just surprised I have not heard of anyone talking about him before, auto hit 1 damage at ranged seems hard to top.