now it's based on recent damage

But obviously not a DK.

Death Strike has always healed, it used to be based on # of diseases on the target, now it's based on recent damage.

Bloodshield isn't based on overheal, it's based on just flat out the heal.

70% pure avoidance would po wow avoidance cap any DK tank raiding. Naxx 2.0 taught what happens with pure avoidance % gains (unholy tanks able to keep boneshield up at all times because we were only getting hit 5 times a minute).

How would this mastery scale up with points? Higher % of avoidance? How does it trigger?

WTF does D&D have to do with a thread about mastery?