If I were to nerf Kalista, I would...

I would do one of these three: (not all)

1. Get rid of the must finish attack feature on her passive
2. Put up a limit to 5 arrows per enemy on her E
3. Make her ultimate allow the others have a choice. (they chose if they want the arrow on the ground)
4. Kalista's attack speed is nerfed to 5.98 (because late game, that speed is insane)
5. Her Rend instead does AP
6. Take away Sentinel's passive