"We're changing DP because Spriests are too bursty in PvP, this will be a PvE buff and will buff mastery"
"We're changing Glyph of MS because Spriests are too bursty in PvP, even though we know this is a slight nerf to PvE DPS and mobility, which we also realize are issues"
"We're changing DP back because we went overboard with PvP nerfs, so mastery will go back to being bad and DP will actually get slightly nerfed. "
"We're going to buff Mind Blast 20% even though we did all these nerfs so Spriests in PvP aren't as bursty, and if you happen to choose DI and enjoy the randomness of the talent, you'll suck a tiny bit less on mobility if you get lucky with a proc. This won't help all that much with scaling, but hey, at least it sort of looks like we know what we're doing."
So some of our nerfs happened because of PvP, but at the end of the day, PvP Spriests might just be even better off while we're not as good as we could have been had he kept DP as a more traditional DoT.
If he would have kept DP the way it was, and buffed MB, that would have sufficed for me. Mobility still would have been lacking, but at least our single target DPS would have been more where it should be.