There may be something wrong with Jhin's crit chance
ADC is my least favorite role, but when I do play ADC I barely ever play anything but Jhin. Currently building crit is the only viable build on him (not really, Jhin is sitting on 47% win rate...), and I started suspecting that there's an inherent issue with Jhin's crit chance that makes even the currently-only-viable crit builds not work properly on him. I usually rush IE first item as Jhin... and I've always felt like my crit chance is far lower relative to having 20% on other ADCs. It may be just my imagination though. Here's what I realized; Firstly, it's important to note this - there's an "anti-luck" system in place: (quote from wiki)
Critical strike chance will adjust dynamically based on the number of basic attack that didn't critically strike. At 30% critical strike chance, if you basic attack without critically striking, your critical strike chance will temporarily be increased to 60%, and if you fail again, it will be increased to 90%, then to 100% if you fail again. The critical strike chance increase will reset whenever you critically strike.
It's possible, again I'm not sure and I may be entirely wrong about this, but if Jhin's fourth shot is regarded as a critical hit, thus resetting his effective crit chance, he gets far less value out of crit chance than other ADCs. He may be cumulating effective crit chance as he's missing his first three shots, then resetting it on his guaranteed fourth shot, and starting from 0 on his next round of four shots. This makes any crit chance below 100% less effective on Jhin, especially on the lower numbers.
Can this get looked into? Again, I may be wrong, but I just don't know anymore.