I agree about the different heights. But I understand the developers — apparently, it really is difficult to implement.
However, I’m confident that they’re working on it. There are so many requests on this topic. Too many to be ignored 
If you don’t mind me asking, where are these frames from? 
Lucifer ( series ) / Mazikeen gifs 
Hahaha. I teach 4th grade (9 to 10 year olds) and some of them are almost my height!! Perhaps there should be a height slider/randomiser?
Exceptions don’t break the rule.
Yeah, I get where you’re coming from but, in my case, it’s sufficient to have enough lots per city available. Mostly because once my zois become young adults, they usually move out of their family home to get their own space. That’s why I understand that 8 zois per household can be limiting for a lot of players, but in my case, I usually deal well with it. Have been doing so since Sims 1-4, so I’ve gotten used to it now xD
I do wonder if this is why the decision was made originally to have them be the same height but it is very confusing in a game.
It probably didn’t make it into early access.
A height slider would be ideal, and if I recall correctly, this is a major issue with the Zoi models when it comes to implementing this feature in the game after the fact. It’s actually a necessary feature—in real life, people come in different heights and body types. The request to age Zois via cheat codes or through a selection option hasn’t been implemented. As Samuriko suggested, that would be a good way to customize Zois.