I've realized that this spell has massive damage potential in pvp, perhaps the most sustainable damage in the game. The DD portion of the spell (the only part that matters damage-wise) does 1300 damage for a 2 second cast time. That's 5k aoe damage in 8 seconds, which comes close to killing poorly some clothies. Over the same time period a mage's blizzard would do 1.5k damage. SoC's aoe radius is 15 yards, compared with 8 yards for blizzard, or 10 yards for AE. I think some players don't realize how large this radius is and don't or can't spread out far enough.
All this makes SoC devastating in certain situations such as defending the bottlenecks in AV. These create target rich environments where you can position yourself to be protected from melee attack. I've topped the damage charts doing this, and it's not because I have great gear. SoC scales horribly with gear.
Of course this tactic has an obvious counter, which is to dispel the dot. But it may not be so obvious that four players have been hit with SoC - it's not like you have shards of ice raining down on your head. Then boom - everyone's dead.