This isn’t really at you, but I put this here to give an idea or something, and also because I don’t really want to make an entire post.
Another one is if people learn how to play against him. I stomp him easily with nasus and garen even though jax’s Kit counters most of my two main’s kits. All I do is just bait out his stun and walk outside the range of it. If he uses q to get to me then (as nasus) I wither him right before to lower his damage against me or (as garen) W right before the e is re-activated to lower the stun duration and to increase my resistances.
The reason why jax is so op (mainly talking about low elo in this sentence) is very similar with garen and nasus, people don’t really know how to play against them, which makes it easier for the jax nasus or garen to snowball and win.
Now don’t hate me or anything just because I had a couple of good games against jax, I also played jax myself so I do know what I am saying. Jax gets op when he gets a lead and finishes his powerspike items early, but he is absolutely shit when he is behind.
a good nerf is lowering his attack speed/AS growth because he is an auto attack based champ (unless he is going full ap), but I think that lowering his AD is a good start.