Qiyana as a champion is in a akward position u cant damage buff qiyana or damage nerf, a damage buff could make her more overpowered so smurf can easily abuse her and a damage nerf can make her the worst champion, so she would only need a fix. The biggest problem about qiyana its her mana, in her early laning phase she can easily get harrased and abuse and all i can do is forced to use my ability to cs so trading with qiyana is irrelevant in alot of matchup, in some hard matchup i am force to run doran’s shield just to sustain early laning phase which its really bad, in the early phase u are meant to have more balance experience and qiyana doesnt seem meet that. Qiyana now feels like a worser version of kassadin. The only way to fix her is to give her mana buff for early laning phase this would not make her op or weak this would make her more balanced. I would acknowledge a rioter to put alot of games and effort in her if they want to see it for them self.
IMO, just nerf stealth duration on Q.