Ok, well this shows she's still a polarising character, I guess - fair enough, and to be expected. I am surprised, honestly, that you've switched from indifference to outright hate based on eps 6 and 7, though. I'd wager that's not a typical reaction, and whilst I can't speak for DPC's intent, I think there's a lot of evidence that he's tried to make her more sympathetic in recent episodes.
It may well be atypical, but I suppose I had a similar reaction. Early on I thought Quinn was going to be a fun frenemy to a CHICK MC, someone we'd constantly be trying to one up; the look on her face if you throw the Cumpetition is priceless. Eventually, I figured that would lead to a new phase. Maybe she'd mellow out, or we'd gain a bit of grudging respect for each other, or maybe it would lead to sharper barbs that finally became decidedly unfriendly.
Instead, we learned that Quinn was in a lot deeper than it first appeared but also that she was much less competent than we thought, too. That pretty much took the fun out of trying to one up her. Unfortunately, as
D2M3 said, that's also when we saw Quinn start to take her frustrations out on everyone around her. As a result, while I don't hate Quinn, I do find her an unpleasant person I have no desire to be around - at least when viewed as a character.
As a player, I think Quinn is a great antagonist because she's well written character who has a distinct personality and clear goals that drive much of the story. But ultimately I'm rooting for her to fail. If that finally makes her see reason and turn her life around, so much the better. But the important thing is for Quinn to stop making everyone else's life worse.
Wait, is there a split where you lose out on Bella if you're with Josy/Maya? I haven't seen that. So far in my game up till where EP7 ends, I'm successfully wooing: Maya, Josy, Sage, Jill and Bella. I've lost Quinn/Cathy/Jade and womp womp, don't get that SAUCY Nicole/Sandy scene if you keep Jill going.
Currently Maya/Josy and Bella are compatible. In fact, Maya/Josy will even help the Bella route by forcing you to turn down Cathy.
I'm starting to wonder if the Main Girl paths will wind up compatible with each other until much later, but will wall you off from the side-girls fairly quickly.