Just a little "experiment" i thought about:
What's the net loss for a fight where Smite-/holyfire-healing is viable, to change 1 DD + 1 heal by 2 disc?
I heared about Discs beeing able to get up to 14k DPS and 14k HPS by just spamming HF/smite. That's just the pure throughput, and you would need the other healers to spike-heal, what's - depending on the fight - quite more mana inefficient.
Still.. do are my numbers about right? And would it be viable at least in 25 man?