Nerf Kench's Tankiness Instead of His R Damage
I think it's really interesting to have Kench as a massive damage dealer when he gets into range and it gives him other viable lanes like Top and Jungle too. If his damage is nerfed, his clear times will suffer and I think the main issue people find with Kench isn't just his damage but rather how hard he is to kill.
Anyway, I'm pretty sure he's overrated. I mained Kench JG a few months ago and while he was certainly good late game, he also had many weakneses that make me believe he's not the best pick. For one, his clear especially pre-6 is awfully slow and a bit vulnerable. Secondly, his ganks are mediocre (especially until you get Dead Man's Plate). Of course, they can become very good if laners overextend enough for you to use your ult. but overall, his ganks are not particularly strong. Moreover, while he is insane in skirmishes, he falls off a bit in teamfights since he does get kited and lacks strong AoE. I dare all the "Tahm Kench OP" players to try him out a lot more because I'm sure he doesn't deserve quite the ban rate he has. He's annoying but he's not as strong as he seems on paper.