offhand as in half hearted, not your toons left hand. Cause i've already figured out all the arguments against doing this and am simply doing this to pass it along rather than let it die.
What if they make mutilate available for other weapons. But at a reduced +base damage output.
What i mean is,
Attacks with both hands + 101 damage to both weapons +50% if you have poisons on the target.
Since swords [et co.] have higher base damage, make the +base bonus to each arm less depending on what type of weapon class your weilding.