Moot point. Ours will benefit from Mastery in 5.2.
It wasn't moot in regards to what Taymage was saying....
Er, yes, it is, because he was directly responding to someone saying, "The final 4 Challenges modes I need will likely need to be healed by someone else". It was a direct reference to 5.2 and the expectation that they won't be doing well.
So, yes, completely moot point.
This is pretty much what just happened:
Poena: The final 4 Challenges modes I need will likely need to be healed by someone else
Tay: One wonders how any other healer could possibly keep a tank alive in challenge modes, given they are currently putting up only 200% crits, as opposed to your current 200% plus DA. [implication: our healing will be roughly equal to other healers as of 5.2]
You: They gain Mastery on non-crits.
Me: Yeah, just like we will in 5.2, meaning Poena is just Chicken Littling.