Anecdotal evidence isn't evidence. This post adds nothing other than "I made a change and my healers thought I was easier to heal."
Just as a random fact that was interesting for me:
I was one of those tanks 'stacking' mastery, I have, 4tier pieces, and 359 iLvL, meaning, my gear doesn't suck, and it's not perfect either. Anyways..
I decided to 'reroll' stats, and go for Stamina, just for a while, to get my epeen higher on the meters, and as a surprise: At the end of the week, all of 'my' healers told me that I was easier to heal this week.. And one of them said: Well, with more mastery, you still got hit, and had less Health, but with more stamina, you Still get hit, but have more health...