Healing on a controller is not difficult at all (i heal on a ps4 with controller, raid as sch in FCoB, and know many others who heal at a competant raid level on controller), and targetting people through the party list is only an issue if you are not a good healer in the first place. Many people use the controller as an excuse sadly, rather than look at what they can do to improve their own healing/game.

Although i commend your solution, it is a solution to a problem that doesnt really exist, and to some extent, a solution that just further complicates the matter.

Also, to test this out properly, i think you would have to go into much much much harder content.