I'll need to see the rotation but having Chain Heal baseline brings Elemental and Enhancement back on table. Being able to blast this x4 is why the Druids are strong using 4x Wild Growth. The problem with Wild Growth on Druids is it drops you out of boomkin form, so you lose a GCD everytime you use this heal (and you also lose the armor)
Adding on top of this Healing Stream Totem, and you should be able to do a 1x tank 4x Ele for PvE and this should also work well for PvP. Too bad Shaman didn't get that fabled 4th tank spec. THAT would be something.