We have the story equivalent of spaghetti code here. If you change one part, you’re forced to alter lots of other parts it’s connected to.
If Mai hadn’t met Yuuichi, she wouldn’t have created the demons. No demons means no noble task to keep her going. But then, Mai as we know her wouldn’t even exist. She would be the frail, crying girl we get a glimpse of near the end of the route.
That would suck, so other excuses are needed to keep the story as close to the original as possible. Let’s say there’s a reason for demons to appear regardless (no love involved? Oh, come on!) - but it would lessen Yuuichi’s importance and disconnect him from the demons issue completely. If your current crush tells you to stop fighting demons, it can’t even compare to your crush of over 10 years who’s also the reason for them existing doing so.
The way I see it, no matter how you change it, it would always lead to cutting out several layers from both the story and Mai’s character.
