Yeah! Starting off with SWP->MF til orb proc is great of you want to sit around waiting on RNG all day, losing DPS. I'm sure there are a couple situations where it makes sense, but most of the time when I tried opening this way, I just lost DPS.
I myself have found that during Dark Arch Angel, casting Mind Spike and Mind Blast to be significantly higher DPS.
The issue being that it is not mana efficient, so is not always the best option, particularly if its a fight where you wont take much damage to proc masochism or a longer fight.
With how shadow word death has been revamped, and with the new healing mechanics making healer mana a premium, has anyone else noticed how much backlash damage SW: D is now doing during the execute phase? With dark evangelism, flasks, and double trinket procs, I have pulled off over 60K SW: D crits, and on double crits that can be nearly 50k backlash damage.
Sometimes the double backlash damage is a boon, but on certain fights where raid damage starts flying out (council for example) SW: D execute becomes a liability. Lightwell offsets that to some extent, but it can be very annoying to play around.