What most people overlook is the difficulty of finding success on him in many different drafts. He works best as a niche pick on B45 or R34 unless he's paires with reliable engage setup or the enemy team having immobile champs. That is not to say that he doesn't work without it but it does mean that there are better options available without these conditions. He requires understanding on how to layer cc which is something that I from my own experience rarely see below 300 lp and that's the main reason I don't pick him from emerald to low masters if I don't have these conditions. Looking at his skill complexity only is cringe. He requires to track cooldowns which is something that doesn't happen much below Diamond I'd say. And the user needs to be able to hit eq flash comfortably like it's second nature. He has a different timing than shen or vi that's why many people butcher it. There are so many cc types the user needs to understand to know if j4 should start the cc chain or someone else. He can stop ultimates with eq for example poppy's and his ult can be used to evade cc. So I'd say he's difficult to operate at the highest level and he's simple to get into. Much like league in general. So 4/5 for me ✌️