I like these ideas.
1. Milestones would be good for knowing what inclinations you can get. Achievements would give the player goals and hints towards storylines they could do.
2. Banking could add a crime system like thieft/mugging, which would mean you could probably do crime career yourself. Would also make you able to drop your wallet like NPCs do.
4. Calendar events gives another common reason for going to town besides work, buying clothes, and living in an apartment.
5. More property with more rooms means more roommates and since a lake is planned to be added, a vacation house would make sense.
Netural idea
6. Your reputation changing how people treat you could be both bad and good. I think the current system gives the player more control over their perception, but I wouldn't mind random events based on the current system.
I don't think is a good idea
3. This is a game about college, being in college for 18 years for them to grow up doesn't make sense. If they could grow up in a few months then incest could unintentionally be added which would be bad. So that would require a lot of systems to be added just for this one idea that isn't really needed, such as parenting, tracking of relatives, adding NPCs to the existing pool, and etc.