I'm not so sure that dark intent was that big of a nerf for us. Last week I did 63k on heroic 25m Halfus, which topped my previous high by almost 9k DPS---and that was before the changes to dark intent. Last night in the same fight I beat last weeks DPS output and did over 69k DPS. Maybe RNG has worked to my benefit each of the last 2 weeks, maybe its because I'm with a better guild than I was with before, or maybe I am getting better at being a shadow priest....but the damage loss seemed very insignificant. I did almost 6k more DPS on valion, but suffered about a 1500 DPS loss on Twilight Counsil, and stayed about the same on Cho'Gall.
So I'm not so sure we were hurt that badly by the changes to dark intent