Originally Posted by
yehyehyehyeh
Actually the opposite is true most of the time. Remember how in Cataclysm they had to keep buffing Unholy Might (+10% str) to allow unholy to stay somewhat competitive? The reason is very simple. Unholy scales bad with weapon damage. In PvE you use lots of Scourge Strike/ Festering Strike and those scale with weapon damage so in PvE it's not as bad. But in PvP you use Necrotic Strike/Blood Boil/Icy Touch alot, and those don't scale at all with weapon damage.
For example if I would replace my T1 wpn with the T2 weapon, my Death Coil/Icy Touch/Diseases/Blood Boil wouldn't get any noticable increase in damage (except the increase from more PvP power) because they will only benefit from the small extra amount of strength on the T2 wpn compared to the T1 wpn.