Meh... I'm in my ult for like 2-3 seconds during the combat phase...
I'm not sure what you're talking about kiting her ult... She's way too fast to kite anything. You'd get one hit in before she's on top of you. Maybe if you hit her with CC, sure... then yeah she's as good as dead. But no ADC has enough CC to stop Valor from getting to you in the long term. (except Tristana)
Like I said... I can ult in and wombo combo almost every ADC without taking any damage myself... So that means even if an ADC manages to hit me with a slow and kite me... they better kill me in the next second or else I'm killing them anyway. My all in is so strong that I can still win the fight even after taking multiple hits and slows.
Ult > E > Ignite > AA > Blind > AA > AA > BotRK > Ult
Literally deletes 95% of ADCs... even if they are a level or two above me. You can't move, you can't AA, you can't heal, and then when you finally hit me with damage, I use my BotRK active to vamp it right back off of you. Then you try to flash away and my ult gets the cleanup kill. Happens so often it's like clockwork.
The only variable is sometimes the ADC will flash away... which does nothing but lets them survive an additional 3 seconds... because I don't even need flash to catch up in Valor form.
In fact... if I run into a situation where I dive an enemy and they are actually going to kill me, I can quickly flash off for a disengage, wait for my skill cooldowns (still in valor form) and then vault back in and wombo combo them all over again for the kills. I do this often against some stronger melee champs (usually I don't need to flash out unless they lock me up)
So that combo looks more like:
Ult > E > Ignite > AA > Blind > AA > AA > BotRK to recover some HP > fly away for a moment to get skills off cooldown > E > AA > Blind > AA > AA > Ult
That takes care of tankier champs.
Of course for the ultra tanks I don't bother ulting at all... since I can just poke them from range and vault if they get on top of me. Then if they are nearly dead I can always ult in to get a cleanup if they are trying to escape.
The only time Quinn fails is if she ults in on multiple enemies... which is what a lot of Quinn beginners tend to do. They see a team fight, they ult in, they dive an enemy... they hit ult again.. do literally no damage and then get deleted, and immediately think Quinn is trash.
I STILL have problems doing this sometimes... usually when I see 1-2 low health enemies surrounded by full health enemies... I think I can make some sort of pro play, dive in, delete the 2 low health enemies and then somehow disengage... But all that happens is I get hit with a ton of CC and die before even killing anyone.