I'm playing Mutilate right now. It obviously sucks not having Shadowstep in MoP, but playing without Sinister Calling is what ruins it when comparing Assassination to Subtlety. 30% total agility on a BiS Alliance rogue amounts to about 40.
Sinister Calling also increases your damage done with Backstab (we won't have Backstab in MoP) and Hemorrhage (rogues will have Hemo. in MoP) by 40%
4.3.3:
Assassination:
Assassin's Resolve: +20% melee damage, +20 energy with daggers
21.31% base crit (26.31% for Mutilate with Puncturing Wounds, although I prefer Quickening)
309 attack power
34.13% dodge
Subtlety:
Sinister Calling: +30% total agility, +40% damage for Hemorrhage
Opportunity, Imp. Ambush: +10% damage for Backstab and +25% damage for Ambush
26.14% base crit (86.14% for Ambush)
385 attack power
37.93% dodge
/bored