Just a few things I've found helpful. First of all more mastery (armour) is good yes but on this fight say you're taking on average 50k dps from the bleed. You manage to go all in mastery and get 6k more
mastery than you currently have! (This is probably really high) With 6k more mastery you get about 3% less physical damage taken...
Damage Taken: 50000dps
Decrease in Damage Taken: 1500dps
New Damage Taken: 48500 dps
You`re going to take 1500 less dps for 6k off stats!!!!
Now let`s look at 6k more say... crit.
Around 36% crit you need about 580 rating for one crit out of bear... in bear you only need 387!
Therefore 6000 rating gives 15% crit!!!
Ok this is a little over the top but you get the idea... you`re looking at 1% crit for every 100dps less you take... think of all the rage.
If you want to work out you`re stat weights and how much rage/sec you're getting I have a ton of stuff posted at http://theetova.blogspot.ca/