I hate to say it, but can Kalista be fixed?
Firstly, I'm by no means a Kalista player nor main. I don't even main ADCs...buuuuut...
Tying her attack-speed to her Oathsworn is a terrible idea. It's an ADC, not an A&SDC (Attack & Support Damage Carry(?)). And even worse, it's per level...So she's labelled as a permanently lategame champ for her already atrocious early game due to her Oathsworn needing to be around for her to be at top damage.
And funnily enough, her total attack damage is still at 90%, just because of her hopping mechanic. She doesn't even build attack-damage oriented items until later, so this pretty much helps mess up her early/midgame damage (bork is only 25 damage). All she really needed was to have her dashes be reduced if slowed by cc...and she got that...but other nerfs weren't reverted. If anything, her W max hp% should be per level, since it's leveled last anyway.
I actually like Kalista as a champion, as obnoxious as she was at launch. Facing her as an immobile melee champ is a joke. But dumpstering her is not the way to 'nerf' her.