I just got Ancient Aqir Artifact (Sorry not sure how to link it to show the stats). Anyway, I am currently at 494 Defense and using Autoblocker and Pocketwatch as my trinkets. Curious if I should replace one of these with the Artifact? I should also mention that I have Coren's Lucky Coin as well. Just trying to find the best combination to use.
My personal suggestion is to run with the Coren's Lucky Coin AND the Autoblocker. Since you're uncrittable, I don't think there's enough use for the Artifact unless there is another major defense piece that could be swapped out for something better.
Basically, if you find yourself getting killed by mobs or your healers are burning mana fast keeping you healed, then run with The Pocketwatch and Artifact. If you're staying alive just fine, stack the Block Value trinkets and go to town with 6K shield slams.