+50 Attack Power, actually. Which is +50% of your weapon's damage added onto the total, effectively, rather than a modifier to the total damage after powers.
Oh, I based my comment off of the wiki. So my paladin is sort of a side-grade to that build (no shield or heavy armor, so +25 to all attacks), and ttk isn't as absolutely ridiculous as I thought.
I thought the only white mage spells that used your weapon were Charge Weapon (stance), and Smite Evil. And if you're running thief anyways, the latter is directly competing with Dastardly Trick. Maybe I just don't understand how the math works, but wouldn't DT have more raw damage under most circumstances?
Dastardly Trick does +200 attack power and +50 accuracy, plus a stun or stagger. Smite Evil has +50 accuracy and deals bonus holy damage based off of your spellpower. At 71 spellpower, Smite Evil's damage bonus is 86 holy damage, and if you're using the War Scythe or a similar heavy weapon that's 50 base damage. At 17 strength, along with the Champion's belt, that's 61 attack power before powers and perks.
Now, I'm not certain about the calculations, but I'll give two sets of numbers for Smite Evil. The first assumes that SE's bonus holy gets modified by attack power, the second assumes not.
1: Without twist the knife active, This champ would have 136 damage multiplied by 1.61, leading to 218.96 damage.
With twist the knife active, that's multiplied by 2.11, for 286.96 damage. I don't know if it rounds up or down, or even just is a floating point behind the scenes.
2: Without ttk, that's 50*1.61 + 86, resulting in 166.5 total damage.
With ttk, that's 50*2.11+86, which is 191.5.
For Dastardly Trick, without ttk it's 50*3.61=180.5 and 50*4.11=205.5.
The numbers I had for the one using Smite Evil aren't really optimized, the willpower doesn't have starting bonuses and the spellpower boosting equipment is just the Amulet of Transference, the Witch's Hat, and the War Scythe, so willpower could be raise further. But essentially, if attack power does not impact the Smite Evil damage bonus, then Smite Evil outdamages Dastardly Trick when your spellpower's high enough to provide 100 or more flat damage (assuming you're using a weapon with 50 base attack. More or less changes the effective damage boost threshold). If attack power does impact the Smite Evil damage bonus, then it can outdamage Dastardly Trick even if your character has no willpower investment and only has spellpower bonuses from the Amulet of Transference and the Witch's Hat and no sources besides.