#0 - Oct. 28, 2010, 6 p.m.
In the case of paladins and warriors, we have recognized that it is possible for block chance to get too high too quickly and cause a situation where stacked mastery and the warrior Shield Block ability behave strangely. Since that's a scenario we want to avoid, we're making some changes regarding how block chance is handled for each of these classes:
Paladins - Holy Shield will be changed to increase block value by 10% (40% total) instead of increasing block chance by 15%. Since this will cause Mastery to become more valuable, the amount of block granted by Mastery will be reduced to 2.25% block chance per point of Mastery, down from 3%.
Warriors - At level 85, the value of Shield Block decreases as block value generated by Mastery increases. To remedy this, we will convert overflow of block + avoidance that exceeds 100% into critical block chance instead. Along with that change, Shield Block will be reduced to +25% block chance (down from +100%), but this will still yield a net buff for most warriors. Also in response to this change, the amount of block and critical block provided by Mastery will be equalized. Finally, Mastery will now grant 1.5% block chance per point.
Additional upcoming tanking changes can be found here: http://forums.worldofwarcraft.com/thread.html?topicId=27397548532&sid=1&pageNo=10#188