1:Afaik Mind Flay can crit now.
2:Shadow word
eath has a 1,5 second cast? Since when?
3:When did shadow priests have a spell rotation? You are either being sarcastic or not a good shadow priest. That being said, it is true that there are more spell rotations, which depend of the encounter and/or gear.
1) Vampiric Touch > Shadow Word: Pain > Vampiric Embrace > Mind Flay ... basic, mana-efficient
2) Vampiric Touch > Shadow Word: Pain > Vampiric Embrace > Mind Blast > Mind Flay > Mind Flay ... with better gear
3) Vampiric Touch > Shadow Word: Pain > Vampiric Embrace > Mind Blast > Shadow Word: Death > Mind Flay ... mana intensive spell rotation
Obviously VE can be simply removed out of it, some guilds use it, some don't. I thought the rotation was pretty much obvious, at least it was to me when I played a shadow priest for a little while and reading here that SPriests don't have a spell cycle just pissed me off.