It's in SimCraft now, so I ran the numbers for warlocks.
We know that the proc copies the damage done on a random chance. This means that the dot tick will be copied, not the dot itself. We don't know the proc chance by spec, and it appears that Blizzard is able to change the proc rate on a spec by spec basis.
So rather than wait, I figured "Hey, lets just do every % that seems likely."
This is our baseline:
http://simulationcraft.org/410/warlock_auto.html
Affliction (Shadow Bolt) 29160
Demonology 26723
Destruction 27549
First, I gave each profile the staff with full stat values, enchanted, with 3 Brilliant Inferno Rubies, and set the proc rate to basically 0 (0.00001). This gave us a baseline. From here, I increase the proc rate by 1% at a time and plot the trend:
Code:
Base 1% 2% 3% 4% 5% 6%
Affl 31590 31865 32083 32338 32576 32853 33057
Demo 29804 30021 30217 30448 30607 30824 31033
Destro 31568 31837 32048 32293 32541 32784 33036
I can then take these values and find out what % damage increase we get on a point by point basis:
Code:
Base 1% 2% 3% 4% 5% 6%
Affl 31590 31865 32083 32338 32576 32853 33057
Demo 29804 30021 30217 30448 30607 30824 31033
Destro 31568 31837 32048 32293 32541 32784 33036
The averages are:
Affliction: 0.78% DPS increase per 1% proc rate.
Demonology: 0.69% DPS increase per 1% proc rate.
Destruction: 0.76% DPS increase per 1% proc rate.
For those of you who don't like percentages, this works out to an average of:
Affliction: 248 DPS increase per 1% proc rate.
Demonology: 206 DPS increase per 1% proc rate.
Destruction: 243 DPS increase per 1% proc rate.
Please note that this degree of separation is so tiny that RNG, fight length, player skill, etc are all more likely to make a bigger difference than the staff itself.
---------- Post added 2011-06-27 at 01:14 PM ----------
To make it perfectly clear:
We do not know the proc rate of this staff.