I think what s/he means is that Quinn's early game isn't as strong as it used to be. Pre-rework, two consecutive Harrier procs at level 1 would chunk people for about half their health, if not more.
Her assassinations aren't really as swift and easy to pull off anymore, either. Before, with Valor, you could just E to a target and get a guaranteed Q off instantly, provided you clicked fast enough. Now, you have to aim your Q -- which is vital to the fight because it's the hardest-hitting ability in Quinn's kit -- and make sure you're not getting blocked by minions while you're at it, since you're no longer smack-dab in the enemy's face.
Not to mention her old Q was just plainly better at fighting fed ADCs with than her current one; or at least, it required much less finesse.