Sorry I never got back to this earlier:
Obviously they'd have to be Agility, as it gives attack power and Dodge.
I'll admit I had trouble tossing together ideas that put emphasis on purely Crit/Haste/Mastery (so you would just share Hunter/Enh gear) without stuff like "Haste = Parry now!".
One could argue that the addition of Parry to Flurry isn't quite maintenance-y enough for such a huge boost of avoidance for little to no thought.
Basically it would be broken down by this:
- Crit = Flurry which means a big Parry boost
- Haste = More chances to Crit (for Flurry) & faster mana return for more use of their Active Mitigation buttons (which don't get the 75% mana reduction).
- Mastery = Bigger bubbles for less damage taken, obviously.
As far as putting it some sort of 'stat order', I have no idea. That would require actual tuned numbers or something.
I would guess that you'd want some sort of base amount of Haste for steady use of Active Mitigation, as well as a goal amount of Crit to keep up your avoidance as much as possible. I'm not quite sure where Mastery would fit into that equation. Even though it has the possibility to be really powerful, I'd venture to guess that it would be primarily ignored until you can get your Crit/Haste situation figured out a bit more.
Again that's just guesswork since I have no idea how numbers would actually come together.