Wasn't kalista gutted because

It was mostly a combination of her high AoE damage (Rend + Runaan's Hurricane), high mobility (passive), high durability (lifesteal + Sterak's Gage + Maw of Malmortius) and her ability to kite teams with a little assistance.

Kalista was gutted because she was frustrating to play against and her mobility made her oppressive. Jhin is a marksman/assassin.

It was because of how her mobility worked.

Kalista, like Azir, is too overloaded to be balanced. Jhin's only problem is how high his numbers are.