Winter's chill x5 or 5x scorches with improved scorch give 10% crit
My last post was assuming you were going after a heroic team with no elemental shaman in group~

I personally heal my tank with earthshield + riptide and throw in a healing wave if needed, and then the group (which are stacked up and auto following my tank) get slapped with chain heals when they're not at full, but that's all preference really.
tbqh I wish I had a priest healer but I'm completely burned out on leveling characters