Cho is quite balanced and has weaknesses. His Q can be dodged if you are quick enough. He's mega slow especially when he hits full stacks. Most people by late game start to kite him and CC him a ton, and he does eventually die. How is he a "nightmare?" He's not that bad compared to say Zed, or Fiora or whoever. He's just a mage that goes tank and can deal a butt load of damage. Not that different from Darius or the other tanks that can deal tons too.
I think you just got wrecked by him and are crying for nerfs. When really you just need to learn how to counter him (LuLu works great, he comes close to Q or W, just Whimsy him). You're no different from all the butthurt people crying for Annie nerfs because they didn't know how to stay away from her/counter her and she got off a 5 man Tibber stun.
Calm down. Look up tips and counters. And stop QQing.