This is a good question. Considering that Hunters are so over the top op'ed, they need multiple nerfs in the opposite direction.
Such as: Increasing UTH to 3 mana, along with it only creating 2 hounds (not based on opposing minions), or 4 mana, based on opposing minions, but they don't have charge...
Probably completely do away with tracking and/or flare...no reason they should have the ability to burn anyone's secrets, and/or completely hand select cards..
-Increase the "kill random enemy" spell to 4 mana...
-Increase the cost of buzzard, or limit the amount it can draw per turn to 1.
-Decrease hero power to just 1 dmg.
As far as buffs go, I'm not so sure as that changes everything...But nerf the hunter as described and they'll still be competitive but more in line with all other classes.