Well now AMR is telling me to re-gem and re-enchant all for haste instead of mastery. Anybody have any idea what changed?
AMR is likely wrong. Here are the 6.2 weights for CoP SPriests
Int (1.00) > Spell Power (.91) > Haste (.85) > Crit (.76) > Multistrike (.66) > Versatility (.64) > Mastery (.62)
//edit: And if you swap between Auspicious Spirits and CoP, your averaged weights are
Int (1.00) > Crit (.97) > Spell Power (.91) > Haste (.84) > Multistrike (.71) > Versatility (.67) > Mastery (.55)
I mistyped. It has always been mastery and now it has changed to haste.
Your Mastery: Mental Anguish changed, nerfed in strength by 10%. This has reduced the importance of mastery stacking, likely to balance against the Repudiation of War trinket. This would have the effect of buffing haste's value, as you'd be able to get more trinket-buffed DoT ticks in.
Damn. I had almost 98% mastery. That's quite a nerf for me.
muahahhaaha - I've been doing it right all along!
I think haste was probably the top stat all along. A 10% adjustment to the mastery talent likely isn't large enough to make mastery suddenly drop from first to last place in the stat weightings. More likely was that haste was a solid first, with vers/mast/mult approximately tied after that. Since Mastery was the only stat to take a nerf, then it would drop to a clear last place.
Update: looks like the mastery change was reverted instead of a 12% nerf to Devouring Plague in late June, right before live.
We're back to square one on explaining why haste is suddenly weighted higher with the same gear.
Looking back at 6.1, Haste was also worth 1.5x Mastery in T17 gear for CoP. So it appears nothing actually changed, rather the weights you were using were outdated.