Quinn feels useless when behind

Pre 5.22, Quinn was pretty bad unless fed or early game going top. But at least she had a ranged blind and a decent escape through her ult. So she could provide some utility/have a way to lower her chances of feeding.

Now, she has no utility other than high mobility which is actually detrimental when behind because it encourages going off by yourself since no one else can keep up. This combined with her low attack range and her only escape now being her E (which usually just causes you to jump into death/CC since you aren't untargetable while jumping towards your target) really makes her an easy target and make it very difficult to contribute anything when behind.

All other ADCs offer some form of utility, long range, and/or a mobility ability they can use to disengage (i.e. doesn't have a long cast time and doesn't put them in danger when using it).