Isn't the real insult to ninja that despite the class fantasy being a dual wielder, they don't actually use the off-hand item slot? After all I would be surprised if they ever let a combat job that wasn't paladin use it and it wasn't just for shields. There is white and black mage, but we all know they gave up with them in ARR in letting them use the off-hand slot.

I honestly expect viper's weapons to be like ninja's weapons, in that its one item in the primary slot, so no mix-n-matching using the off-hand item slot.