One item I forgot completely about yesterday is the Vengeful Gladiator's Dragonhide Helm. It's much less easily obtained than the Vindicator's Dragonhide Bracers, but it is in a slot that is notoriously hard to upgrade, it is a big upgrade from the Stag-Helm of Malorne in terms of stamina, and it provides a ton of resilience as well. Using this will allow the same setup as yesterday save that you can now use the Band of the Swift Paw and Slikk's Cloak with only using one resilience/defense gem. I chose the helm itself for this, as it's likely you'll also be using this in your PvP gear set.
The helm, by itself, gives 470 HP over the Stag-Helm in bear form. It also provides hit rating, crit rating and armor penetration; it's very good for threat. For mitigation it is not as good as T5 or T6, but it is better than T4 overall and can provide 1/3 of the resilience needed for uncrittability by itself while being a better option than T4.
Even better, when you combine it with the chestpiece, you now have a 2-piece bonus that gives all the needed resilience for uncrittability. It also happens to perfectly work with a fire resistance set and will serve well for fights into MH and BT.
In general, I think you should go for this as your first piece of arena gear - especially if it is unlikely that you will be able to get the helm off of Vashj any time soon. The Vindicator's Bracers are excellent for the time when you don't have that helm or you want to replace it with T5/T6 (which you should). Given most guild's reluctance to farm Vashj, chances are that you'll have this for quite some time.