I haven't run into roomies leaving notes out yet. Someone else posted a link to the different personality traits that they can have in a semester. There might be more specific terminology for that.
I didn't really notice them during the first semester. In the second, I did notice the tendencies more. Some would fix items, some would bring food or throw parties or have a girlfriend. There was a "clingy social" guy who would follow my sim around but then wasn't actually that friendly. Sometimes there would be random music. I haven't had a crying roommate yet.
That sim lived in Wyman Hall which has a few private rooms, so he got that type of room both semesters. I didn't realize that the other dorms didn't have the option of a small private room. My sim would just close the door on everything and go to sleep.
I slightly overhauled Darkwing and I actually like it without having played it. I might be sending him there with his girlfriend who is finishing high school. I just opted to let him go home for a little bit while I've switched to playing her as she finishes being a teen. I'll try to see if I can send them together in the same semester and household. I can tell that Darkwing could either be turned into a sorority or into a more quasi-residential place. I'm playing it like the latter.
I will say, I like the world but already, I'm wanting more lots. :-) I could do with a few more residential spaces for off-campus apartments in Britechester itself.