Jhin isn't one of the ADCs who were "gifted" an escape. He litteraly has nothing. His only source of movement speed is from his passive.
I play Jhin quite a lot, and let me tell you : I don't always escape, even if I'm Sonic the Hedgehog at that point.
If I don't dodge everything that's thrown at me while I'm running, you can bet that I'm going to die 100%.
https://i.imgur.com/m14EcJ5.gifv
Here, for instance. Why did I live?
1 - The Jax AA a minion and not me.
2 - The Pyke failed his Q
If that Q landed? I was dead. He thought I was gonna go towards the mid tower and thus aimed that way, but I was aiming for a minion to get movement speed, so I "dodged" it.
I litteraly lived thanks to my enemies' mistakes.
https://i.imgur.com/VKymJqN.gifv
Then, this instance.
Nothing much Vayne could have done in my opinion. With every auto attack, I procced
and Fleet Footwork.
However, if she had flash, I was dead.
Looks ridiculous? Yea, I can get that.
But this is litteraly all he has. Jhin is so easy to lock down, so the mobility coming from his passive really helps when it comes to positioning and surviving.
There is also the fact that Jhin NEEDS to auto attack CRIT in order to get the movement speed bonus.
I mean come on. You have to litteraly shoot the one who's chasing your butt, which is really risky. You're giving them an opening each time you stop running to auto attack. Sure, it's a short window of time, but let me tell you that it's enough for some champions to kill you.
I don't know why people are complaining about Jhin's passive lately. It's been like this for a while.
Strangely, people complain about it after a match against him... :o
Come on, let the guy alone. There's other things that are much, much more annoying than a Jhin going fast. ( in my opinion at least )