The most broken thing on Jhin is actually that trap
It deals more magic damage burst than some full build ap mages' ult.(1000+) Aside from that, his high AD is fine, seriously fine, don't ignore his attack speed. It's the missing hp damage make his crits incredibly hurt, without that, he deals the same damage on auto as other ADC.
My opinion is nerf his trap scaling and missing hp scaling, and he will be balanced.