Updated for Battle for Zendikar.

Out of curiosity, why did you go with Black instead of Red where you can have access to cards such as Tormenting Voice and Magmatic Insight to trigger Sphinx's Tutelage?

Mostly because I prefer Black's ability to outright kill creatures. I'm almost certainly going to be less explosive than Tutelage, but with access to hard boardwipes and killspells (rather than the Anger of the Gods/Radiant Flames and Roast-type spells), I think I'm a little better positioned for the long game with Black. And that's just fine for me.

Might want to update your Mill Package description, because it still says Dictate of Kruphix

Good catch, thanks.

New updates:

Added 2x Complete Disregard, 3x Despise, 1x Send to Sleep (sideboard)

Removed: 1x Ruinous Path, 1x Scatter to the Winds, 1x Send to Sleep, 2x Murderous Cut, 1x Negate (sideboard)

I would suggest taking advantage of the Retreat cards. Your board wipes wouldn't affect them and they would use no mana passed initial casting to stay alive and if needed, scry. Between tapping until you can afford the mana for those wipes, and gaining some life, it should keep you in the game long enough to mill that much easier.

Retreat to Coralhelm

Retreat to Hagra

Needs some alt win cons, maybe mainboard the Sires and play 4. Then 2 Silumgar of your choice.

I think one more ob mix in the main would work just fine!sunergistic with the draw power.

Thing in the Ice is likely to be the next big thing an UB control decks (see - The Shadows Beckon !!). I must admit to being very conflicted about keeping in Sphinx's Tutelage, but having both wincons in a deck might be a good idea.