You're not wrong definitely ways to make them stay but it will have to have some "love" scenes. Because you have to make her fall for you a believe there's good deep down inside you. So, she essentially falls in love with you while you don't with her and when her friends ask what you see in this guy she'll say he has a good side. Even if it doesn't exist. She will believe it does. Did he say he was reworking chapter 1 again?
But dropping all dark scenes with Nikki is a hella mistake. If that's what Neons going for because Nikki's already the most hated LI in game don't know why I love her and I liked her original look when she came to the door in chapter 1 the first time. She's so hated she's been patched out of the game lol I can only imagine what it'll be like if she no longer has dark content haha.
If he goes a dark love route he just needs to remember that NIKKI loves MC. MC doesn't love Nikki he controls NIKKI. It's tough to write but it is a trope for a reason. As for realism this is a relationship that is as real as time itself they have documentarys on why people stay in abusive relationships. Just throw lifetime on.
It's a trope, yeah, but in order to really sell it, Neon would probably have to have Guy go full on violent psychopath stalker mode. I mean, just based on how I'd expect it to play out in my own mind. A lot of those women you hear about that stay in abusive relationships, they have
partners tumors that will severely entrap them by beating them, controlling who they associate with, where they go and when they go, and things like that. They'll also scare off ANY guys that the victim remotely shows an interest in (or even ones she doesn't), whether romantically or otherwise. Is that Guy's character? Is that Nicki's situation? I guess I'm not sure; my leaning is more towards 'no', though. Especially as another commenter has said, Nicki has already run away 3 times from abusive men, and it doesn't look like Guy's situation is any more dire or dangerous than theirs.
Regardless, that'd be a big commitment on Neon's part; for even just
1 girl, much less a dozen. I think in the long run, it would just be a strain on Neon in regards to trying to make it work in the narrative, but also on the audience's suspension of disbelief. Before anyone scoffs at that last line, I believe Neon has clearly had that on his mind throughout the execution of this project, adult VN or no. There's a reason this game's popularity has grown so rapidly lately, and imo, it isn't because it mimics the design choices of every other game

It's because it's a breath of fresh air that follows the logic of its own world and characters within it that it's taken the time to setup.
Anyways, that's all just how I see it. Other people here I'm sure would disagree with me.
Yea I don't doubt he will like i said Harley Quinn to his Joker. I mean yea you have to get her a flower once in while that doesn't mean you can't have freaky sex once in a while either. Besides power corrupts if he wants to and keep it realistic. He could turn Nikki into a female MC every bit as fucked in the head as him when on dark path. Because if you live a life without consequences, it will likely fuck you up.
People very, very rarely change their personality in such drastic ways. That's almost always porn logic, which again, I think Neon is trying to avoid as much as possible (within reason; it is an adult VN after all). Would also end up being too much narrative leg work I think, so I don't see that happening. But if it makes you feel better, he already has 2 female characters that will basically be dark-triad partners in crime. They're not main characters or LIs or anything, but they'll give us a kinky lil taste of a lady on the dark side right beside us
