One of the more intriguing general class changes on the 5.4 PTR has been the complete redesign of frost mage mastery. Frost mages currently get Frostburn, which deals extra damage on specifically frozen targets and adds extra damage from their water elemental. With most bosses being immune from freeze mechanics, you can imagine this mastery doesn't do much good for PvE mages. Thus, the redesign on patch 5.4 grants frost mages Icicles, which allows them to do more mastery-based damage in all situations.
Death knight masteries aren't in quite as dire straits as the frost mage mastery was. Blood Shield, in fact, is downright solid. Our DPS masteries, on the other hand, are rather bland, being straight elemental damage buffs. They also come with some compatibility problems which causes the mastery stat to turn out low value for non dual wielders. With that in mind, this week we'll speculate on what Blizzard could do in the upcoming expansion to make mastery a little more enticing for death knights, especially for DPS.