I got to play around with Disc last night. Back when I was raiding a lot, I went with the haste & crit heavy build. I used that equipment set. 20% haste unbuffed, 20% crit unbuffed. Low mastery.
Healbot wasn't updated yet, so all I could do is Holy Fire, Smite, and Penance. I specc'd into From Darkness Comes Light for the free flash heals.
Has the coefficient for Smite changed? I was hitting 70k+ crits regularly. Holy fire wasn't hitting nearly as hard (maybe half). It's a fast cast in my haste heavy set (1.24seconds), with very low mana consumption.