My advice would be to run your shaman with the group and follow one of the questing level guides. XP per kill wont be all that hot, but you will breeze through quests like theres no tomorrow and level fast. Just set loot to free for all. I had a priest and 4 mages group and swapped out a mage for a paladin. with RAF to 60. I went to outlands and used Jame leveling gude 60-65. Im about half way through it and it says I should be level 63, but im about 5% away from 65 right now. Things just die with 3 mages doing your bidding and your shaman gets to pick up the peices.