A lot of people here will argue this until they're blue in the face. In my opinion, Quinn is going to become a love interest. Officially, she's never really been considered a love interest by DPC and as far as I know, there's never been any love points for her but of course, I haven't dipped into the code/script files for this game in a long time and my memory sucks.
The way her story is shaping though, tells me and a few others that Quinn will become a love interest or at the very least get an ending. Like I said though, a LOT of people here don't want to see that happen because of a misunderstanding of Quinn's motives and actions.