Graves, the OP

Does anyone else agree that Graves is currently a tad overpowered?
Immediately, from level 3 in dominion, he often seems to take away about 50% of my health (champion dependant) with just one ability.
I heard he's getting a nerf soon (perhaps todays patch), but he is now part of the free champion rotation - time to give him a whirl to see what the hype is all about.

Do you agree Graves is OP, or if not, who is?