Mastery over haste Aff PvP

[Natixsphere]

Ok so I understand what mastery does and why it is good for warlocks but why did it change the stat priority for affliction pvp? I would think that the more haste we have the faster our dots tick which has always been the case. Is it because we would lose out on other stats if we did go all hamster for affliction? If anyone can clarify this I'd appreciate it thanks!

[Darkrulerxxx]

More mastery in combination with pandemic means longer ticks with more damage buffed from mastery. For our timing abilities we already have Dark Soul: Instability that gives 30% haste in which we can use in conjunction with our dps cds. The Mastery stat is just too good to pass up compared to haste or crit.