Yeah, it's just HORRIBLE to have a mastery that really digs in most just when you need it.

Deep Healing beats Echoes of Light (Holy Priest) if the target is at 58% or below in pure throughput, and without the six second delay; if somebody drops below a sixth of their max health and you hit panic mode, Deep Healing has twice the throughput of Echoes of Light.

Holy Paladin bubbles have the same strength as Echoes of Light, except that your target has to take more damage for them to matter.

Disc priest mastery has twice the magnitude of Echoes of Light or Illuminated Healing.. except that it only applies to bubbles (and consequently, it has the same limitation as the Paladin mastery, although it's more under the caster's control.)

Symbiosis (Resto Druid) has the disadvantage of taking two spellcasts to activate; it's still weaker than Deep Healing once the target drops to 51% health.

I can see where it throws a spanner into theory crafting; nobody's had to care where the raid's average health was to evaluate anything before. And, of course, it varies by the fight; the first boss of SFK is going to make Deep Healing look very, very good, while Ozruk tends toward binary health; you either don't need healing or you're dead. "Hard to evaluate in practical conditions" is by no means equivalent to "Useless," however.

As for the 'randomness'; it's not random. It's not consistent, but predictably so. And in a GOOD way; the more healing the target needs, the more they get.

That totally explains why Shamans are the best healers right now. We're totally topping the effective healing meter according to the statistics. As it is, we're so good that we're taken before other similarly geared healers especially Paladins and Priests. We bring so much to the raid in terms of buffs that no other classes can give (like totems and heroism those 2 are the best buffs in the game!). We also have the best cooldowns in the game. Yes, paladins have 5 cooldowns, but Nature's swiftness is so good it beats all those 5 cooldowns rolled into one. We also have the best mana efficiency among healers. I mean we get so many free spells (Paladins only have 2) it's amazing. Mana Tide Totem is also super awesome since I stack spirit (not haste or crit before spr). Don't even get me started about Mastery. It's so awesome it's the best mastery bonus among healers because targets are always below 58% (even after I heal them). Man shamans are so awesome I could totally see raids stacking Shamans right now. When raid leaders think healers they automatically think Resto Shaman. We're that awesome right now.