Welp, I tried max E Quinn a couple of times and was just not really impressed, guys.
You're giving up so much of your burst damage when you don't max Q first. Forget about the blind component, the ability does damn near 2x the damage E gives you. The 1 second gained on the cooldown just didn't do enough for me. It doesn't make E spammable (or otherwise allow you to use it liberally) during the laning phase and it doesn't give a meaningful damage boost. If you have 3 points in it early and E onto someone like Riven or similar for harass, you're still going to get all-in'd and fucked up unless you have a flash available...so it's really no better with one or two points than it is with max points until later in the game when items and levels make it a 6-second cooldown or so.
It's entirely possible I didn't adjust to having it, but I felt like I was being pretty aggressive in both games. Finished those 2 games:
14/3/10
8/1/5
But felt damage-deficient early because I didn't have a strong Q. One of the matches was a Nasus/Garen that were kinda rotating between jungling and laning. The other was against a Singed/Vayne that went back and forth between lanes. Both games rotations were happening because I was putting my foot deep in their asses. They went mostly as expected. Any time I'd get too aggressive, they'd try to turn it around burning one or more summoner spells. Usually immediately after I used E for continue harass. It was funny fucking up Nasus' last-hitting with Q, btw.
So yea, the only time I could really feel like that's the right approach is if you can't land your Q's effectively. It's certainly not the best skillshot in the game so I can understand just getting a point in it for the unlikely blind you may actually land...but I'm pretty effective with the blinds. If for any other reason...eh...Quinn is so squishy the difference between a 10 second and a 7 or 8 second E cooldown if you're being all-in'd is irrelevant. She's gonna die anyway.
Now, if the E got a buff where the move slow amount or duration increases, I'd have a different opinion. Like if it was 20%/30%/40%/50%/60%, I'd understand maxing it first. Or if the duration was 1/1/2/2/3.
FWIW I did a bit of due-diligence to see what the guides offered up by diamond players are suggesting and they're all maxing Q first.
http://www.lolking.net/guides/101215
http://www.lolking.net/guides/181620
http://www.lolking.net/guides/170936
YMMV, of course. Build her as you find most comfortable/conducive to your winning.