I'm currently evaluating the best possible stat priority for my friends affliction warlock for PvP. I'm looking at a lot of top rated warlocks and they, of course, put all possible stats into haste. If a piece of gear already has haste, and they are hit capped, then they go into mastery.
My question is, with a haste break point at 9778, why do top rated warlocks have 11k+ haste? Shouldn't they substitute the "unnecessary" haste into mastery? What exactly is the reason for this? Is there something more that haste does that would completely over rule the damage you WOULD gain if you put more into mastery?
TL;DR is 1200 or so haste stronger than 1200 or so mastery?