In what way could a Generations pack differ from its Sims 3 counterpart?

I think it would be an opportunity to go deeper on the age stages.
I would particularly like see something done about their 19-going-on-20-the-first-day-of-becoming-a-teen sims.

The first thing I want to do with teen sims is kick them out the house because they look so old.
Their immediate focus is University. I need a stage between child and teen where they look like they are ready to explore the early stages of teen life instead of looking like they missed it.