Well, took my undergeared DK+ Ret team into the arena for the first time last night (which was 2 nights after they got 85). Their iLvl was 329-330 since I just got access to herioics an hour before.

Went 10-10, with most of my losses to the same 2 teams, which is why I finally went to bed. All of my toons are at about 100k hp, and 300 resil. The healing the team has is insane, and it is definitely a burst race, who can kill who first. The teams that won usually killed a pally (or two at the same time) first, where as the teams that lost were usually focused on my DK, only a couple of which successfully killed him.

Most of my wins were from wrecking a dps in the first few seconds, gimping the opponents damage and CC. I am only using two heal buttons atm, none of which can target a specific pally to heal, which is definitely my biggest weakness atm. My 2 healing buttons are 1 button for all 4 Pallies heal my DK, and one for each pally to heal the next pally (so they benefit from 'protector of the innocent' and 'selfless healer').

This team has amazing healing, and pretty damn good burst. Guardian of the Ancient Kings (GotAK) is only really a strength buff, but popping it right away gives it more time to charge to 20 stacks, which is a very helpful + 20% strength. I might later on save wings for when I get all 20 stacks, but for right now I just pop wings + GotAK and start wrecking.

With a frost DK main, seal of justice is not needed, so I'm trying to decide between seal of righteousness and seal of insight. Mana has been an issue in a few matches, but only on 1 pally, which is why I tried seal of insight, but righteousness yields nearly twice the damage. The cleave effect of seal of righteous will make Hungering cold fall off immediately unfortunately, so I'm thinking seal of insight + glyph of seal of insight (in place of templar's verdict)

Since I'm not using seal of Truth, as I don't think the DoT is very good for arena anyway; and Inquisition does not necessarily need 100% uptime, I dropped my points in [Inquiry of Faith] down to (1/3), yielding:
http://www.wowhead.com/talent#schZbbZcbGsdksddk

I'll post more after I do some more games/ get better gear, but this comp looks awesome so far.