Jhin is a mid laner just ranged AD? I can see him work there, Ranged AD Caster.
Just like Varus he can press W and kill 2 minions waves before they hit the lane? Bouncing Grenade sounds like Bouncing Blades from Katarina and they seems to do alot of damage because they killed minions in spotlight. His E is to control his lane? unless minions detonate them. He might not scale from attack speed but his skills seems to do alot, is he an Ranged AD caster like Jayce?
Everything in Jhin Kit looks very very mid lanish. I mean his W is straight and bottom lane is curved. I'm not going to play him as an ADC 100% sure because he does increase damage on lower hp his enemies is soo even if we have an ADC he still seems to do alot.