I did that with my alliance pve team, works well indeed. Problem is after you get good at it, you will run up on the 5 instances/hour limit. You could go armory to cath and then reset. I did this when they had the Headless Horseman quest, so level 70's were all over the place. As soon as I came out to reset, it was gank city. Maybe it's better now

I'm working on 5 shamans now the old fashioned way, via quests.