This is the forum for helping you out if you're stuck or if you want to discuss the nitty gritty details of the dungeons within Mount Grimrock. Warning: forum contains spoilers!
Does dual wielding give any benefits? Does your character attack with both weapons or only those which is actually clicked? I'm trying dual welding daggers on my rouge and it doesn't seem to change much, but i haven't done much of a testing to be honest.
It gives you a choice of two weapons but I don't believe it gives any other advantage whatsoever. You're also missing out on holding a shield or torch or other useful item which you probably don't want to be doing.
I've found it to be quite useful with a rouge using throwing weapons to have both hands have a type of throwing weapon (ex. throwing knifes and rocks), saves time giving him more weapons. Its also useful to give a mage a weapon in addition to a good staff so he can attack quickly if you need him to.