Ive been thinking about our mastery a little lately seeing as how bland it sounds. Would it be so bad to have a Cata Paladinish mastery?
Add to thick hide - Gives you a 35% chance for your armor to absorb 30% of incoming damage. Chance and Amount increased by Mastery.
Mastery - Increases your chance to absorb by .75% per point of mastery and increases the amount absorbed by 1.5% per point of mastery.
Numbers would need balancing of course as i just pull these numbers out of my A%^, but it would make mastery a little more interesting for us.