Several have posted that maul is overpowered, and I agree completely. It is easy to acquire these weapons, and, once you do, you pretty much own everything that does not have a very high dodge rating.
My suggestion would be to make maul come with a penalty. This is supposed to be a form of going berserk, right? Well, how about maul including a loss of control over where the hero goes and who the hero attacks? I think it would ruin maul completely if there were a chance the hero would turn on allies, but there could be a percentage chance the hero uses his moves going off in a useless direction.