Wukong's Passive Is Outdated
It's a nice-ish passive, but lets be honest: its old and has little or nothing to do with his lore or personality.
First lets look at Wukong's mentor, Master Yi: Passive :- Double Strike: After landing 3 basic attacks, Master Yi's next one within 4 seconds strikes twice, dealing 50% AD bonus physical damage which applies on-hit effects and can Critical strike icon critically strike.
^ This makes sense because his weapon of choice is a sword and he is a master of his fighting style. See how the passive compliments the personality and background of the champion?
Now lets look at Wukong's passive: Passive :- Stone Skin Wukong gains 4 / 6 / 8 bonus armor and magic resistance for each visible nearby enemy champion.
.... What? Does seeing lots of enemies give him a hard-on? Is being surrounded by enemies his fetish?
I understand they're saying he's a thick-skinned primate, but he isn't. Gorillas are "stone-skinned," but Wukong is a monkey, they are NOT stone-skinned. (Source: Typing 'Gorilla' and then 'Monkey' into Google Images)
Plus there's so much more they could be doing with his passive. He's a monkey wielding an enchanted staff, maybe give him some monkey mobility or sustain?