So, I'm powerlevelling my new team (aimed at PvE 5-man instancing), which consists of paladin, priest and 3x mage, when it strikes me that priest may not be the best choice for healer, especially with WotLK coming out.

My train of thought is: A priest brings shielding and a sta buff along with his healing capabilities. A (resto) shaman, however, brings bloodlust/heroism, which is mad dps with 3 mages in the party. Add to that a spell dmg increase totem in the expansion, a spell haste increase totem, a selfres, resistance totems, earth shield, elementals not to mention mana spring totem.

Is this an easy choice in the shamans favor or am I missing something here?