Shout out to Riot for Twitch

Twitch should have his poison stack infinitely but the actual stack damage deal less damage. This means if he interacts more often then simple small pokes he will deal more damage and may be able to do things Kalista can do but without the mobility that she has.

My build with Twitch: if I have a support that can protect me I usually skip the boots and build cleaver for the penetration, because of the movespeed on phantoms. I have two phantoms on every auto attack based adc because I would rather have extra crit, attack speed and movespeed over the shiv passive. Twitch is an auto attack based champion, this addition to his kit would make him stronger than he is now by a lot, considering Kalista has a jump every auto attack this is very fair IMO.