Quinn

I am actually pretty fine with Quinn's 525 attack range. She has her Q to mitigate/prevent auto-attack harass from the enemy laner(s), and can counter-harass with her E + passive then retreat from the movement speed boost she gets from W. Also, you must be joking if you think Vayne is easier to play than Quinn. Vayne has very complex but very rewarding mechanics due to the importance of positioning with her Q and passive, as well as using E correctly. One wrong move with Vayne and she's toast as she is so squishy compared to other adc champions. Quinn on the other hand has her E, W passive and ult to disengage and has easier to learn (But still not easy) mechanics.

Because they like Vayne more than Quinn!

Quinn is my waifu and it makes me sad she doesnt have a good enough attack range!

Her attack range needs to be increased, but with that being said, I wouldn't want the distance on her E to be longer than it already is. There are quite a few champs, given the right utility and items who after being hit by E can escape rather easily. Mebbe Quinn just has a poorly made crossbow compared to Vayne though, lol.

Yeah, they say quinn is supposed to counter vayne. But how is quinn supposed to proc passive vs a vayne when vayne not only out ranges, but can just tumble or out range even more with condemn. You can't pre apply AA too early for passive, because it won't proc, since its coded as an "AA modifier", and not a mark (which makes no sense) . And when passive finally "marks", even thought its not a mark, against enemy adc, you cant apply it because quinns range is so short and the enemy adc will just play safe until it goes away. No worries though, it won't apply for another few minutes. the more i play quinn in ranked, the more I realize Quinn needs either buffed, or just a rework already. And I used to be an avid supporter that quinn didnt need buffs or reworked.

Her Vault range is 700 so even with the range difference she can get into the enemies face, blind them and the out duel them pretty easily.