Quick shadow priest question

[Klaus]

Basically, ignore it. Actually, interrupts on mind blast are more annoying than interrupts on mind flay, but even mind blast works ok in combat. The limiting factor on how fast you can kill things isn't spell interrupts or health, it's mana consumption, which is why PW:S is not (IMHO) the most efficient way to go, and why shadowform really helps.

For the longest time while soloing, my most effective routine for killing most mobs was:

Mind blast from max range
run backwards away from the mob while casting SW pain
Keep running backwards until the mob comes into flay range - immediately stop and flay.
(for slow mobs, you can usually get 2/3rds of a second flay in before they reach you)
Mind blast again
wand until dead. - I always made sure I had a good wand.

With 3 points in improved mind blast, the second mind blast will be ready about a half second after the first flay is finished, so you have very little wasted "standing around waiting for cooldown" time.

I very rarely bothered to shield. I usually only used it for elites (preshield and wait for mana to regen), mobs with high attack speeds (makes it really painful to get the second MB off) or in emergency situations. For mobs with slower attack speeds, I would wait for them to hit me and then start a flay. I could frequently get 2 of the 3 ticks in before they hit me again. If they're really* slow (PvP warriors with big slow swords, for example) you can actually get a full flay in between each weapon hit (*whack* flay.... *whack* flay...)

I saved VE mostly for nasty elite mobs or multi-pulls. For a regular mob, it wasn't usually worth the casting time (screws up the rythym).

Later I got the martyrdom and focused casting (now gone) talents. I would use FC about every other fight to get 2 flays in in place of the second MB. Sigh. I miss FC. But martyrdom is still very nice - you do your normal thing, and when you get critted, you whack flay.