I also got terrible results from frost spec. No aoe threat (wtf is howling blast for anyway?), not even good single target, and bad survivability. I went blood and never looked back. Survivability is great, lots of self and group healing, I don't really have to heal anymore.

Here's the spec:
http://www.wowarmory.com/character-t...vrouwv&group=2

And the macro (I start group pulls with DnD though):
/castsequence reset=8/combat Icy Touch, Plague Strike, Pestilence, Death Strike, Blood Boil

I tank VoA 25 every week spamming this stupid macro, against people doing 8-10k dps and I've never lost it. I don't know why it works so well but it does. With hand of reckoning spam on the paladins in heroics my DK always gets the threat back without a taunt.