I hate that we can't just make university students like in Sims 2.

What I've started to do to manage this is to move my sim into dorms, and then use CAS to change all of the ugly townie roommates into sims I want in my game. Then I just leave them to go through university, and they'll graduate around the same time as my sim.
Once my sim graduates, I can go into manage households, turn on neighbourhood stories for them, and move them into my neighbourhoods. They'll have gained friends and enemies from uni, as well as skills - so they've developed a backstory without too much involvement from me.