Jhin is immune to attack speed slows

It's because his AS doesn't change at all. He can't build it, he can't lose it

Let's also not forget to mention that he gains both Critical chance AND bonus AD from building Crit chance. It's another Yasuo issue, which will make him impossible to balance. He will come out of the PBE too powerful, and then either be left alone, or nerfed slightly, turning him into fodder at best.

You sure? Wouldn't that temporarily lower his total AD? o.O

It should work just like slowing Hecarim, or applying persistent armor reduction to Rammus, or standing next to Gallio with Abyssal Scepter.

https://youtu.be/r-Xo_2F9JJY?t=20m54s

He gets Withered and doesn't lose AD around this point.

Also, Galio, Rammus, Hecarim, and the old Lucian ult all lost damage if their condition was lost. Galio loses magic resistance, he loses AP. Rammus with armor and AD, Hecarim with movement speed and AD, old Culling with attack speed slows had fewer shots. They don't lose their stats past the base value, but modifiers change the numbers until that point. If Jhin builds attack speed to get AD, then losing attack speed should lower his AD. It works that way with other champions, so why not him?

Attack speed slows specifically target your attack speed stat. They do not Target your "bonus attack speed %".

Im not sure why he wouldn't have reduced attack speed (its already pretty slow), has anyone tested this to be sure his attack speed doesn't actually go down? or his reload speed?

Watch Boxbox play Jhin top against Nasus. Wither doesn't slow his attack speed at all, and neither does Frozen Heart.