So far it seems that blizzard doesn't want Mind Spike to be used in PvE. That's ok for me, Shadow Priests dps is quite fine. But here's a compromise: make a glyph that allows Shadow Word: Pain to stay on the target when we use Mind Spike. That way we can still benefit from our mastery, which is already quite useless, and shadowy apparitions and still have to make a choice between massive dottage and direct damage burst.