I started out today with an affliction reforge (high haste/high mastery) and decided after the raid to go destro - I ran a sim with that affliction reforge (think it was 6700 haste and 7200 mastery or something to that extent) and it returned something like this: crit: 2.20, haste: 2.0, mastery: 1.7. Following that, I ran some reforge plots (started with 5000-500 and narrowed it in to 500-50 (amount:step amount) and basically ended up with the same results. At no point did mastery appear to be the preferable choice.
One thing I did notice, however, was that when I maxed out crit or kept a balance of crit/haste while keeping mastery as low as possible, that the value of mastery did increase somewhat. Right now, for instance, I'm sitting at 2350 mastery and my scale factors are crit: 2.01, haste: 2.10, mastery:2.05. However, that is in no way representative, as any increase/reforging towards mastery would immediately show it to be worse than crit and/or haste.
This is reflected in these charts as well (i've run this with more iterations that showed the same - i just didnt keep the results, so this will have to suffice):
*SNIP*
In the top chart, which is a crit->mastery/mastery->crit reforge-plot we can see that reforging crit to mastery would be a dps loss. If we had to optimise that reforge, i'd have to (acc to the reforge-plot) take out even more mastery. Which I can't, however, since i'm already at my lowest point.
In the middle chart the exact same as above is the case. Reforging haste to mastery would be a dps loss.
I think the reason why the official simcraft (
http://simulationcraft.org/520/Warlock.html) says the priority is haste>mastery>crit is because:
1) better gear - crit becomes noticably worse at higher ilvls - it doesn't scale as linearly as other stats
2) mastery is over-valued in the sim for the same reasons as in my case: Check the profile for the official Warlock-sim and you'll see:
Gear Summary
# gear_strength=80
# gear_agility=80
# gear_stamina=26255
# gear_intellect=21704
# gear_spirit=80
# gear_spell_power=10078
# gear_hit_rating=5099
# gear_crit_rating=8606
# gear_haste_rating=8872
# gear_mastery_rating=3822
Mastery here is very very low compared to haste/crit, which reflects my findings very well as well (when crit/haste got high, the value of mastery increased, but only at that particular level). I'm almost willing to bet that if you reforged that official warlock-sim to follow the scale factors it suggests with that particular reforge/stat allocation, that it'd sim lower.
Guess my point is that you can't trust scale factors blindly.
Anyway, I might be wrong
Great guide btw