Still too early to tell as there are a lot of factors at play:
-DP changes
-T15 bonuses being dependent on Crit much more than Mastery
-If the Legendary Meta Gem's proc uptime is high enough, a mixup of Haste Breakpoints to shoot for
-Finalization of how Mind Flay (Insanity) works; MFI's viability overall vs. other talents in fight types
Personally, I'm holding off on doing a ton of in-depth analysis until later PTR builds.