You clearly have no idea what you're talking about. Holy is vastly superior to Disc as far as raid healing in pretty much every way, shape and form. Just by the nature of Echo of Light, Holy is better at raid healing. The only thing that Disc brings is Power Word: Barrier, which is a HUGE cooldown. It's probably one of the best in the game currently, which is probably the reason its getting nerfed.
Am I happy about it? No. Do I understand it? Yes.
However, Holy in Chakra: Sanctuary is so insanely good at raid healing right now, I would almost argue that its completely overpowered. Doing H Chimaeron and bringing the whole raid above 10k post massacre in the space of about 4 seconds is incredibly crazy.