This is how Cassio should look like

IMO what made old Cassio a lane bully was her old passive, Deadly Cadence and not her base damages. The passive allowed you to spam spells in lane almost nonstop if you maintained 5 stacks.

My idea is why not made the current mana return mechanic into the new passive since again, Deadly Cadence made you a lane bully and get rid of the new stack passive, bring back old Cass base damage on Q (E stays the same or could use a slight nerf since the new reset timer) and you get the healing bonus at 5 points in Twin fangs and the CDR at 5 points in Noxious Blast I think this version feels like you are playing old Cassio again without being an heavy lane bully and you can choose again to play again poke or ADC Cassio

TL;DR: Basically old Cass is back but gets the QoL changes of the new Cass and shes not a heavy lane bully since for some reason Riot doesn't like that -Get rid of the new passive -Make the mana return mechanic into the new passive -Bring back old Cass base damage on Q -Twin Fang stays the same or slightly nerfed since the new reset timer -CDR bonus unlocked at 5 points in Q -Healing bonus unlocked at 5 points in E