Kalista's passive's frustrating interaction with slows
When Kalista gets slowed, her jump animation gets slowed down.
On paper this doesn't sound too bad. But what this means for Kalista is that every slow that affects her, turns into an attack speed slow if she tries to jump between autoattacks.
Standing still and autoattacking allows her to keep her attack speed up, but at the cost of losing all mobility from her passive, which is the very thing Kalista's kit is balanced around.
Combined with her low-ish range, and lack of upfront damage, getting slowed can completely destroy Kalista's presence in teamfights.
A lot of people have suggested that instead of slowing her jump speed, slows should affect her jump distance. Which i personally think would make more sense, since then slows would affect her kiting the same way they affect other champions.
And I can't really see a reason why slows should affect her the way they currently do.
If more people knew that you can just build slows to shut down Kalista, i'd assume her winrate would drop even lower than what it already is. (43% by championGG)
It'd be more like a qol change rather than a buff. But then again, Kalista is the kind of a balance nightmare where she easily becomes pick/ban in competitive, so changes must be made with care.
I'm not trying to state that my opinion about this is completely right, and frankly i might be pretty biased about it because i never actually get to play against Kalista's due to seemingly nobody picking that champ. But to me this just feels like a wonky and unintentional interaction.