Wow that's why i'm hitting "harder" with it than some other abilities that have higher weap dmg multipliers.
As far as I know the actual damage is working properly.
The only reason i like unholy, more atp 24/7 than frost, and the fact that i get death runes (from reaping) and in addition i can blood tap, more death runes 24/7.
Death rune isn't too much of a difference, well i guess for frost that is but unholy i think its a meh change (at least wep dmg went up).