I'm curious how High School Years will integrate with other packs.

I think High School will last as long as your sims are teens.

But I'm also curious about how this will integrate with other packs. Drama Club comes to mind as well. (I actually expect no changes to that)

And while they said there's some impact on University, we can't see what that is until the Gamechangers get regular access to add the pack into their regular games.