I was hoping it would be both, but that'll due, it's still useful. Thank you.
Found it: http://us.battle.net/wow/en/forum/topic/969937068#2
...and I did read it wrong.
It's good that they made it useful, although to different degrees, for all 3 specs; fire benefits most for obvious reasons, then frost with the talent to make it frosty, and lastly arcane with the mastery working on all damage types. I still wish they did something more with ranged AoE for arcane though. I'd like to see something like Overload from the Arcane Protector guys at the top of the stairs before The Curator in Karazhan... Fond memories of saying "You're the bomb GTFO" whenever they cast it on someone in the raid. A unit-targeted ranged AoE like that would fit arcane nicely. Oh well, one orb per minute is better than nothing.