If we do have a Sims 5, should they add a height adjuster in the base game (or in a pack)?

I think height presets would be the way to go. Making different animations for interactions between Sims of different heights could be time-consuming, but it would look better than, for example, having Sim A’s lips clip through Sim B’s nose when they try to kiss. (They’ll have to make sure that all height options are compatible with all kinds of furniture too. I have screenshots of some of my shorter Sims sitting in the couch. XD)