I have thought about it but tanks are more movement dependent. Healers can heal from anywhere. the ability to kite the mob to the spot you want him to be in range of DPS and heals seems to take presidence over heals if you have macros and keybindings set up well. Of course an all hunter group or a Quad hunter and in heal maybe what you are looking for. Pet tanks. As a X5 Druid team fears can position my tank out of position and I need to have control to adjust. I dont use IS boxer yet but i have seen someting called click regions set up with Healbot that looks pretty kool for healing from the main tank screen.