It's hard to say really. Personally, I don't think he should be nerfed as he's in a very good place. And if you were to nerf him, what exactly would you target? His sustain? Any further nerfs to that risks breaking him. His ratios are fine and his two CC abilities are skillshots with considerable casting times while being easily avoided (perhaps not his silence, just his rupture in that regard). Maybe removing the slow after you've come down from rupture? I don't know, I'm just thinking out loud here and trying to imagine what they'd actually nerf if they did.
I guess after discussing that with myself, they'd likely not nerf him?
EDIT: I'll tell you this though, I play a lot of Cho and he's an awesome champion and a lot of fun. The BCP Cho skin is pretty cool, my friend got it for me during the gifting period and I've come to love it as much as I love Gentlemen Cho. I'd say if you have the cash and you don't mind spending it, go for it.