Facial Hair and Height Sliders

All animations are specific to a sim's height, so although it would be easy to make sims different heights - as some CC sliders do - they mess up all the animations and resolving this would require new animations to accomodate all the new heights. And worse still, for animations where sims interact with each other,  all possible heights would need specific animations that relate to all the other possible heights. The number of new animations needed greatly exceed what's reasonable to make. This is the kind of problem AI may one day solve in games by giving it some example animations and having it generate intermediate ones, as needed, but this is a rather advanced route at this point. For now, in a situations where animations are fixed and each made by a person, the chances of them introducing lots of new heights seems low to me.