Lots of confusion regarding stat weights. Different sources give different priorities, but the reality is that there is no definite stat priority. Twintop has posted sample stat weights for different talent combos for given sets of sim conditions, so you can use them as guidelines. Keep in mind though that those weights will vary for different conditions.
Stat weights will vary depending on:
1. Your talent choices. Stats interact differently with your talents, particularly your lvl 45 and lvl 100 talents, resulting in different stat weights for different talent combos.
2. The encounter. Your stats impact your spells differently, so fights where you play single target dotweave (e.g. downstairs Kargath, The Butcher) will have different stat weights (a higher mastery weight in this case) than fights where you play CoP multidot (e.g. Tectus / Brackenspore). Movement, downtime, and encounter mechanics will alter your gameplay and will therefore affect your stat weights.
3. Your playstyle / role. Your stats will have different weights for Kargath if you stay downstairs or if go up, or for Brackenspore if you're doing flamethrowers or not; even if it's the same encounter with the same talents.
4. Your stats. Yep, your stat weights will vary with your stats. Overall, stat weights are fairly close with the exception of versatility. That means that for the same fight, same playstyle, same talent choices, your stat weights will vary depending on your current stats due to stat interactions:
So every time you replace a piece of gear with a piece with different stats, your stat weights will shift slightly.
In conclusion, even if mastery scales a bit better than crit/haste/multi for patchwerk CoP, there is no sporebat right now. Keeping a healthy stat balance will yield you better results than stacking one stat while neglecting another, and it will give you more flexibility.