As I said 10 scoundrel is 33% dps boost vs 50% of 10 warfare. Anything else is anecdotal evidence. I played with a full physical party and rogue outdamages even the ranger once you outlevel the houndmaster and the op uinique Ifan's crossbow and buy decent daggers.
Dual wield does not even remove the offhand penalty btw, so I think you're really confused on how damage is actually calculated.
If you're worried about scoundrel getting worse than knight/ranger with this nerf, it's gonna hit them way more as I said earlier.
And about "equally awful", the game is doable even with a full mage party, but then it actually starts resembling something challenging.
