Elise, Zac, and Thresh have been nerfed like five times already and still no balance. Riot just likes making champions these days who are extremely overpowered with superb kits.
It's really sad to be honest. I think the only not OP new champ that has been released in 2013 is Quinn, that's it.
That's what I'm saying. When has Riot ever really understood their champs, or new champs, for that matter? If they did, you'd get well balanced new champs, instead of horrendously OP champs with a slew of nerf follow ups. :p
Although Elise at least takes some sort of practice. Zac's jump takes a bit. Thresh is just op.