I fear all routes are heading towards a bad ending,or at least mc should lose something very valuable in the end, much like Acting Lessons. And it's definitely something DPC would do.
Back to the introduction of ep1 initially, it said:
# "Either way, I was happy back then. We didn't have much, we...erm..."
# "...we had enough."
# "We had each other."
# "As for now?"
# "Let me tell you what happened."
Obviously it suggests that mc is not so happy now.
For Jill's path, there is a great risk that we see a repeat of the sorry story of Lynette;
For Bella's path, having an affair with a married teacher is dangerous enough;
For Sage's path,Sage is graduating from college while mc is still a freshman. And mc may not be so equal to the headmaster's daughter in position. Also, if you chase Jade at the same time, then you're done;
For Maya&Josy, throuple won't last long. Harem is not DPC's style;
For Others'path(mainly Quinn. Besides sex, I don't think other girls have romantic options, personally), mc will deal with drugs, which Neil warned him about on the first day of school.
However, if Zoey is an available option,I think I haven't noticed any signs of a bad ending yet.