Post by blademeld
First, precise numbers:
179.28 Mastery rating per 1 Mastery
176.72 Dodge rating per 1% Dodge
1 Mastery = 2.25% Block Chance
Dodge suffers diminishing returns
(
sources)
Block absorbs 30% damage (40% with Holy Shield), so in the long term, on average, it negates less damage than dodge.
However, it does reduce damage spikes better than dodge.
This is the goal of reaching 102.4% avoidance/mitigation (A.K.A. the Block Cap).
In reaching the Block Cap, Mastery is the most efficient way to go, it's 222% more efficient than Dodge or Parry rating,
and it doesn't suffer diminishing returns.