So, I figured I'd give the hard numbers as well.
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Rating costs (taken from the game, basically just divide your rating by the % gain at your char sheet):
1% versatility costs 400 versatility rating
1% Crit costs 350 Crit rating
1% haste costs 350 Haste rating
1% mastery costs 280 Mastery rating
As you can see, mastery is significantly cheaper than the other stats. In terms of raw healing throughput, it's a pretty awesome stat. As long as you don't use renew.
Haste and Crit actually give the same stat gain per point. I thought haste was slightly cheaper than crit, consider me corrected!
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The current Ask Mr Robot stat weights for holy priests is:
Intellect 17.76
Critical Strike 10.71
Mastery 10.19
Versatility 10.11
Haste 4.55
Leech 4.14
These numbers should be interpreted as one rating point of critical strike gives you roughly 10.71 extra HPS.
Now, this is not a linear scale! Because these rating points have synergies, YOUR specific stat ratings may vary from these numbers - basically, you should aim for a ratio of stats matching the stat weights!
However, these stat weights also depends on your rotation and encounter. So treat these numbers as a guideline rather than a rule. But as you can see, haste is really getting the shaft this time around, according to Ask Mr Robot - while the other three stats are somewhat evenly matched.
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There is an elephant in the Ask Mr Robot stat weights. Haste.
Is haste really that bad? I am not really convinced. The biggest issue with haste is the mana cost factor. Secondary, it doesn't really do much for our cooldowns. And Holypriest is currently a very cooldown-based spec. But less than half as good in terms of throughput? I fail to really see why that should be the case.