Secondly, you need to Guard more. Heroic Garrosh should spike your to 250k+ Vengeance after he's hit you once or twice (or even not hit you if you used EB as it often puts you over 70% avoidance) which can give you a 700-800k Guard, which is worth 2 or 3 of his hits. With EB and then Guard when you hit 2 stacks of the DoT, you should almost never drop below 35%. If you're using both of these properly (it's not like you die if you don't though) that's more times that heals can go to other targets instead of you. This means more Divine Aegis on raid members, more Healing Rain ticks on the raid to keep AV at 100% uptime, and more Paladin shields on the raid. You'll never actually see the difference because it's incredibly minute, but it is an improvement you can make.