Quinn still needs to be toned down.
She's had one of, if not the #1 highest winrate top for several months now, and she even performs well as jg, mid, and adc. When a champion can thrive in any lane it should be an indicator that they don't have enough counterplay or weaknesses.
It would be okay if she was a "win lane, lose game" champion like Teemo, Yorick, Gnar, etc, but she's not. She wins nearly every top lane matchup and has one of the highest winrates in the entire game.
Her HP is uncharacteristically high for an ADC and she has the highest MS of any adc at 335. I think if she is going to stay in top lane as her primary lane, she needs her range reduced to 500 from 525, and possibly decrease her HP or MS slightly.
To have the strongest roams in the game, she should have to sacrifice something for it. Instead, her pre-6 is extremely strong and once she hits 6 she can use the advantage she almost certainly achieved in lane to snowball even further in other lanes.
top is right up there if not worse now, just not as popular. That being said, she falls into a niche requardless of what she does, she can't adc well comparatively, jungle is ok but niche still, top is the only reliable power she can have over an enemy. People need to remember she is squishy... and She can't really hold off on two enemies very well. in a 1v1 she is powerful, don't let her have that.