You outgear my Pally by a hefty margin, yet I have almost 5% more avoidance than you do (and about 4% more block!). You're stacking threat stats to the point of using a DPS ring that has *zero* avoidance or mastery or anything, and that's what's hurting you. There's a reason that few if any Paladin tanks are seeking out hit/exp, because in 99% of circumstances they're totally unnecessary and you should spend that itemization on defensive stats instead.
Also, the TB trinket would beat out either of the two you're using. Mastery > avoidance, and the resist on-use is very nice (situational, but extremely powerful in those situations).