One of the things I've liked about the story thus far is that there are frequently consequences.
And making Quinn a potential LI means she'll almost certainly escape the consequences of all the crap she's done.
DPC is good. But there are limits to how much divergence you can have in the multiple paths of this sort of story, unless you break it off into 2 stories/games being developed simultaneously.
Quinn is an enemy or a friend, depending on whether you are chick or dik.
It's obvious to Chick that Quinn is a global evil who sells girls for money and sells drugs.
And for Dik, Quinn is a cheerful person who is confused.
By the way, the more often I replay the game, the more I am convinced that a good ending will only be for the chicks. Whereas most likely the diks will have a bad end.
Chick MC is typical hero with positive qualities of character. Yes, he was fucking Riona and Camila, but he must fuck! He is human and he must be experienced in sex to properly deflower Jill.
But Dik MC is antihero without typical positive qualities and endowed with questionable and even bad qualities of character. He was fucking all girls and promiscuous in sex. He fights with other boys, cheat her girls and take a drug. He is bad boy and because Sage, Quinn, Jade and HOTs like him. The route of DIK is way of big risk.
A good plot twist will not even be the arrival of James, but the conditional arrest of MC or Quinn.