You don't really "tank" as such in PVP if thats your focus, however if you looking for stats on a ice power sets for PVP then I'd go for "toughness", "might" and "Power". That will give you reduction in damage taken (toughness), more spell damage (might) and power for a bigger mana pool (cast more).
I play a fire tank, and I focus on "Defense", "Might", "Power" and lastly "Restoration", as I'm only really interested in PVE. But AFAIK Ice tanks aren't all about healing themselves so much as Fire tanks do. Thats the difference between the two classes I believe, one heals for mitigation, the other uses defensive mitigation spells.