Well she's balanced now, so since pros only take broken/overpowered champions she's not on their list. I don't even mean that as a 'hater' or sthg, it's their job after all to win and they have to take the strongest picks for that. I'm not sure if she was picked after the 5.24 nerf
Stats
Base AD reduced to 54.46 from 56.46.
Blinding Assault.png Blinding Assault
Mana cost increased to 50 / 55 / 60 / 65 / 70 from 50 at all ranks.
Damage reduced to 20 / 45 / 70 / 95 / 120 from 25 / 55 / 85 / 115 / 145.
Total AD ratio reduced to 80 / 90 / 100 / 110 / 120% AD from 80 / 95 / 110 / 125 / 140% AD.
There's also the 6.6 nerf but it's not that insane
V6.6:
Blinding Assault.png Blinding Assault
Cooldown increased to 11 / 10.5 / 10 / 9.5 / 9 seconds from 11 / 10 / 9 / 8 / 7.
Nearsight icon Nearsight / Disarm icon Disarm duration reduced to 1.5 seconds from 2.
In any case, she probably doesn't automatically stomp lane anymore that easily, or maybe the meta slightly defavours her?
is kinda weak? I'm not completely sure about all the factors, but with her current kit, quinn is basically stomp lane/roam to stomp game ; so when she is strong/meta she is unbelievably oppressive, and it works both ways (when she is meta it's because she is oppressive)