Im fine with him hurting but he does too much for an assassin. q is like a blitz pull with a slow, so that provides very strong utility. He has an in and out dash that stuns for 2 seconds and has really hard cc, a lot can be done in 2 seconds so it really difficulty to deal with him also being able to freely ult. As a champion he just feels kinda unfair and unfun to play against. He regains like a mad man and can easily get out with invisibility as he dashes away and on top of that he can use after shock which just breaks him. right now he's doing the whole lissandra thing and find it disgusting that he can get away with it.
so here's a few suggestions.
1: make him get punished for using his dash as an escape.
basically do the thresh thing where your rewarded for landing death sentence with lower cds, but if you use it to runaway as Pyke the cd should be doubled to stop him from being a nuisance.
2: lower the ultimates width: his ultimate is incredibly powerful but Its too easy to hit. your we should be given more space to enter the open areas of the x. so why not make the x bigger but lower the width that way he still has leeway with and can even hit form a further range it but if he messes up and doesn't center it, you will be able to dodge it.