I've been finding him a lot more annoying than old AP yi.
With AP yi, you just use your Q, and then hope you get a reset soon before you get blown up (Although his meditate did make this hard) as he had no damage past his Q and lich bane proc.
With new Yi, if you don't get reset straight away, it doesn't matter, because you're still going to do huge amounts of damage with your AA, meaning you can get resets yourself and proceed to slam Q multiple times.
New Yi just seems to have the strongest points of the old AD and AP Yi, whilst giving up extremely little in exchange.
Not OP IMO as cc still wrecks him, just I find the changes annoying.