Both Single and Dual wield stats are so pointless to take over Scoundrel and Warfare.
Why would you take Warfare over Single or Dual Wield?
Warfare increases the damage
done to armor by 3% and +1. It doesn't affect the damage done to health, which is nearly all of the damage one does. That means, it has no benefit after your opponent has reached 0 armor.
Single-hand increases damage by 4% and accuracy by 2%, increasing all damage one does.
Heck, even dual wield is a 3% damage boost, which will still yield more damage than a point towards Warfare's passive bonus, since it affects the health as well.
Did I miss something?