That is what I think too. Testing with swapping pieces left and right from 740-743 gear on PTR gave me best results with
ToF / RoS / AS / Mindbender / StM on everything above 2 targets with something like 28% crit / 28% haste / 76% mastery (mastery gems and enchants... just my live shadow copied over with mostly CoP gear in the bags)
On 3 targets for 4 minutes that yielded like 160k DPS with 2 minutes of StM, without buffs or pots etc... could be way higher. We will be KINGS of any council fight ever.
I also tried something singletarget with
FotM / Void Ray / Shadowy Insight / Mindbender / StM and class Trinket with more haste (about 33%), this also yielded comparable results (but isn't viable for anything other than single target). Could be alright for longer single target fights where you can't game ToF. Also will drop in efficiency when you lose your class trinket.
The only real competition I see is on the lvl 90 row, even though with the current tier pieces it won't be, Mind Bender is way too strong on that short of a CD.
Everything else is kinda set in stone and cookie cutter already.
ToF / RoS / AS / Mindbender / StM (or LotV for dungeons).
And as Djriff already stated:
Haste > Crit > Mastery for non STM and Mastery > Haste > Crit for STM.
That will be all.