protection warrior is welcome for he can take considerable physical damages. even through the fury mechanism and effect of skills have changed a lot, the nature of protection warrior has never changed.
in combat, the main source of fury for the protection warrior is shield slam and revenge. fury is basically used on shield block and shield barrier. so, 7.5% hit and precise are the most basically requirements. you have to use revenge and shield slam more to get enough fury, so you can absorb and take damages. or you may have problems if you miss one shield slam.
shield block used to be a very special skill of protection warrior. it can remove the physical damages in short time effectively. in mop, its cool down time is shortened, and you should have fury to release it. these changes have not changed its status still. especially when protection warrior does not have problems with survival, you can use this skill with heavy repercussions glyphs to keep the lasting time of shield block longer. the damage output of defensive warrior will also be increased.
but shield block is only good at causing physical damages. while facing changeful raids, magical damages are everywhere. shield barrier becomes the most important skill to increase the defense of magic damages then. with the support of vegeance, when you are under high ap, shield barrier can deal with physical damages as well as the shield block.
on the whole, shield block is better when you need tank to output some dps. while you are exploring new areas in game, shield barrier can provide more damage immune to the team. as a great protection warrior, you should make choices according to different situations.