There are several champions that stack someform of passive dmg per auto attack, one that comes to mind is twitch who can stack his vennom up to 5 times. However kalista can stack hers unlimitedly. Should twitch / others like him get infinite stacks to keep with this new 'meta' ?
Honestly, no. Kalista is undoubtedly an extremely broken champion in turns of skill floor with output. She's by far the most mobile champion in League of Legends now, as a super damage ADC that can dodge most forms of cc unless they're targetable, but even with the slows, she still able to kit cause of that ridiculous passive, not to mention that her stacking can bypass blinds, or that she has a 1.5 second knockup ult which can put a tank that doesn't have a good initiate into the fray, or that she effectively nullifies jungler paths for a good chunk of time every minute, so she also has a mobile ward that can see into bushes and follow people that they find.
But give Twitch unlimited poison stacks? He hits you twelve times and that's 400-500 poison damage, so no, they'll hopefully end up nerfing Kalista into a tree or something, and allow other champions to actually have a chance.