What changed?
His Q has lower base damage but builds up damage the longer it stays out, his W now is an auto-attack enhancer and loses it's mana restoration, and the damage reduction is only for 3 seconds while he channels drinking. He can now move at 80% MS when he's drinking. His E has a lower CD and does more damage, as well as stunning for 1 second. They lowered damage on his R. Basically, they wanted him to feel less like a Q-R insta-burst mage to a more tanky mage bruiser who would be more up in your face. Oh, and his passive is on a static cooldown but restores 2% more.
I agree with these changes, they make him feel more like the archetype he was suited towards.