The best analogy for the state of Jhin's balance.

If you put a Diamond player against Silver and Golds, who's going to win? Almost always the Diamond, duh.

The ELOs here are the same as the strength tier of the ADCs.

Does one ADC being good and others being bad make the first broken? No, it just means the latter ADCs are weak.

If you center balance around weak, then you get weak. If you center it around someone good without being broken, then the rest become good as well.

And I'd think the last thing you ADC mains would want is to weaken all ADCs as a whole.

The majority of the reason Jhin is overbearing right now is Lethality, damage creep, and the meta being focused around utility ADCs.

Lethality is cheaper and better in early than crit. Everyone gangbangs botlane. Crit ADCs don't get a chance to scale. Utility ADCs will always be useful even from behind due to utility even if they have no damage. Not much obviously, but more than a crit ADC. Lethality still melts towers as ADCs are supposed to. Lethality AD casters erase squishies as high damage champions are supposed to, meaning the enemy team lost the carries to fight back with.

Once Lethality is nerfed and some way is made to strengthen the weaker ADCs a bit, Jhin will go back into line.

Nerfing Jhin first will Sejuani him when the Lethality nerfs unavoidably come later.