I think I know how to fix Kalista
She can still jump. But there is a catch to it.
Every few seconds, she gains a charge. This charge lets her make her jump. She can only store up to 3 at a time. Her Q lets her make a free jump.
In my opinion, this would allow her to be caught since she wont be able to just keep jumping away from you forever and ignorign your slows. Keeping the charges lets her get out of a bad situation.