Ghostcrawler recently commented on the grimoires via Twitter. Of course since it's Twitter he didn't say much. And as Zagram said it's real early in the cycle so further changes are probably in the works.
He said "warlocks are supposed to use pets, and all pets are supposed to be viable", and if that's not the case then that Sacrifice is probably too good or Supremacy isn't good enough. And he also said that they plan on buffing Supremacy in 5.2.
I think it's important to keep in mind that this tier is a bit of an outlier - they don't want any talent to have a big difference between other talents. Ideally all three should be close. Or at least two of them should be close (like Demonology is with Supremacy/Service).
Honestly, I wouldn't be suprised if they adjust things even further so that Sacrifice is actually slightly worse than the others in terms of theoretical DPS - with the logic being that that the health regeneration, stamina boost, and lack of pet management you get wit Sacrifice should be offset by slightly lower DPS. There's plenty of time to make adjustments to other places if they feel warlock damage is too low.
Edited by Stunlocked, 03 January 2013 - 05:27 PM.