Quinn is in need of buffs

Seeing as you aren't giving any insight on what it is that "sucks" on either of these champions, or how you think they should be fixed, I don't know if anyone can help you here.

Darius is just kited to hell, but if he catches up to you say goodbye. Honestly he could use a rework as well. On how to fix Quinn I feel a burst combo that isn't as easily interrupted, a passive that isn't as buggy, and an AA that isn't as clunky would make her a viable pick in both the top and bot lanes.

Quinn doesn't need number buffs, she needs bug fixes.

Also, fix her AA animation, especially while using passive. It's easier to last hit with AD Karthus without using Q's than it is to last hit as Quinn in early levels.

Honestly Quinn needs an entire rework. The whole idea behind her is a burst heavy ADC with splitpush potential. Her biggest issue is how easy it is to interrupt her combo. If this combo gets interrupted she becomes useless for the next few seconds, at least in the early/mid game. She is an early/late game champion with an early game that is centered around the enemy not understanding how to face you.