Let us consult the master:
Race conclusion:
Troll by far. The two most important racial abilities for the PvP shaman are (in order): Slam, Natural Regen. You might point and say, "but but but, BLART! Trolls have shitty wisdom! And and their resists, well um, they suck cack!!" But you'd be wrong. Read the stats again, and whisper to yourself, "trolls are the best, they really are the best, better than rest". If that doesn't work, go write your own damn guide to misinform the world about the superiority of your effeminate barbarian.