He shits on immobile champs and Riven in lane(thank the Lord) but he is useless vs hypermobility and untargettability. Like Camile or Fio can negate a Q and W without needing to sidestep, also try peeling a well designed champ like Ekko. This is similar to Sion.
I've seen Vayne called a counter but before Cho with
and enough R damage to oneshot was her counter realy. Even Vayne cant avoid the r with RG active and deadmans. I think you will need a lot of feast stacks to oneshot her building tanky now. Q out of that skillshot!
Riot dont want to nerf cho but they should realise he will be broken with the new runes. But I'm not surprised they havent realised. The most obvious rune being Ultimate cooldown reduction lol.