I my self have always played with a resto druid , a very powerful combo but also very skill demanding. They have a lot of cc ( frozen power + hex + stun from wolf + slow from totem + cyclone + hibernation + stun from bear + stun from cat + even bind elemental for frost mage), infinite mana regen ( inervate + mana totem all the time ) and a good survivability (shield on shaman if needed + tree on druid + sc bubble on 20sec cd + barkskin + sham rage + mw5 gheal spam in time of need on yourself or on druid if bursted + grounding totem + spiritwalkers grace ). As u see a lot of work :)) definitely not easy combo