I run with a resto shaman and its loads ezier imo, there are tons of times where my resto shaman is sitting around doing squat, but for the trash mobs and bosses that DO hit hard its much, much faster (imo) to have all your DPS focus 100% just on DPSing and your resto shaman spamming lhw on tank and chain heal on group. I even save lust sometimes for when the group is getting low, just so chain heal can go faster. I almost never, ever have all my shamans chain heal, with the resto shaman + chain heal glyph (hits 4 targets) you get massive healage. Plus I always drop healing totems and my resto drops mana tide when I need to. I also carry 2-3 stacks of water and just spam drink for a few secs whenever I can, I run 99% mana most of the time.