Ideas for improving Quinn to make her viable in Ranked Play
Ultimately, what needs to be done, and i've seen a lot of people agree with this, is to fix her auto attack animations and greatly improve her passive's functionality in how it marks people and who it marks. I've owned her since she's been released and she has been one of my favourite ADC's and one of my highest win rate champions. She can snowball hard early on in the game, but as soon as you're on even footing or even worse, fall behind, it's a nightmare to try and claw your way back onto some solid ground. I don't think she needs a major overhaul, but a few tweaks on top of the fixes mentioned above could go a long way and still keep her on a level playing field in her intended role (though some things I have in mind personally could improve her level of threat as a top lane pick as well in off-meta comps).
Personally, i'm a fan of increasing her range from 525 to 550. In relation to her E, I wouldn't change how far back she jumps off of them and keep it at 525 in that regard, but the 550 range to her auto would make it easier for her to harass for an extra auto at least before they are out of range completely if they have any kind of dash, tumble, QSS, etc. She is already forced into a melee position with her ultimate, having a touch more range seems balanced. (Is her crossbow just not as good as Vayne's?)
When it comes to her passive, I would like to see a little bit of armor penetration added to it while they are vulnerable. 5 - 15 Armor Pen?
Right now, her E scales at (( 40 / 70 / 100 / 130 / 160 (+20% bonus AD)) I don't think it's much, or overpowered to raise it to (( 45 / 75 / 110 / 145 / 180 (+20% bonus AD)) or else just leave the base damage the way it is and increase the % bonus AD. Maybe something like 30% or 40%? Thoughts between those two? Either that, or leave it as is but when you use your ultimate, the base damage and % AD scaling increase to compensate for the lack of marking a vulnerable target with your passive, which is where a big chunk of your damage comes from to balance things out.
With her W, Heightened Senses, not much would need to be done here. The passives for Quinn and Valor in both forms is fine just the way it is. It's like having a built in Phage proccing every now and then. Asking to have the cooldown reduced from 50/45/40/35/30 to 40/45/30/25/20 might be a bit much, which is more of a 'want' than a 'need', but something that makes sense to me is that when you use your ultimate and turn into valor, it could reset the cooldown on your W as a utility tool for chasing someone through the jungle. The whole idea of the heightened senses to me is that it's Valor assisting Quinn in the first place, and now you're playing as Valor. Originally, and this is pretty broken, I thought it would be a good idea to have it active during the entire time you are in your ultimate but not the max range. A bit OP in retrospect, and reducing the range takes away the advantage of using it for scouting when you go somewhere you probably shouldn't, lol.
Now for the Q! To me, it feels like a poor man's version of Teemo's blinding dart. I wouldn't go to the extreme of having it scale all the way to 2.5 seconds, but having it look something like this 1 / 1.25 / 1.5 / 1.75 / 2 seconds would make a significant impact in her mid and late game. Improving the animation would be a nice touch and narrowing its width a bit when fired so you can thread it, but still get that same AoE impact when it hits would be an improvement. To be honest though, i'm not sure how I feel about the 65% bonus AD and 50% AP. The only AP you'll ever see on Quinn would be coming from a Sheen, which isn't much when every build is focused on her attack damage. Maybe it's fine, maybe it isn't. Any input on that would be nice. Maybe reduce the AP scaling and increase the AD a bit more? 70% bonus AD and 40% AP?
Now, last but not least, her ultimate. Knowing when and where to use it is the hardest part. Some of the ideas I like that i've seen have been giving Valor some AR and MR and even increase the duration to 30 seconds and when Valor dies, it pops Skystrike as a revenge dish and reducing the cooldown. First off, 30 seconds seems like a bit long given her mobility as Valor. She could travel around the map and split push for DAYS and make Hecarim look slow, haha. So, gonna scratch that one off the list. AR and MR? Maybe just some armor makes sense for going in against a bruiser. Magic still hurts the birdy. Popping skystrike when you die as Valor is something I really like, but I can already imagine the rage every single time someone kills you with a sliver of health left (remember, 1% for every 1% of your targets missing health) and trading kills. Way, way too strong and better left alone. Reducing the cooldown is something i'm all for though. I would change it from 140 / 110 / 80 to 120 / 100 / 80. I had been leaning towards 120 / 90 / 70, but with CDR (say from BC?) and roaming as valor, may be a bit too frequent?
That's all I got for now. In the end, the main goal is to just make her competitive and on a level playing field with the rest of the ADC's in the role she was built for.