if you think you are leveling to 80, getting playable gear, and starting to arena before this season ends, you are nutts. (unless you are botting
)
in shatter play the mage basically sets up the kills with sheep rotations on healers/key counterspells while the spriest does most of the damage while you assist with big deepfreeze burst during the kill attempt.
someone should ALWAYS be polymorphed. if you are sheeping someone where a teammate can dispel them make sure to rank1 frost bolt them a few times (i usually try to 5stack, i put a few up before hand so its ready for the switch) beforehand to cover the poly.
You and the Spriest are basically the favorite class/spec targets in the entire game for zerg comps like beastcleave so get ready to pillar.
Rshaman also get zerged down quickly so be prepared to peel a lot. (novas, cone of cold, sheeps, deep freezes, fears)