I want improved baby and toddler stages.
I want babies to be more interactive, to be able to be held and moved and not confined to some strange bassinet. I want cribs back, and changing tables.
I want toddlers to be younger. I want them to also sleep in cribs and start out as not being able to walk, but you have to teach them to walk like in the other sims games. I loved that part. I don't like the older versions of toddlers in the sims 4. They're too independent for it to be fun...
Other than that, I want spiral stairs, bunk beds and witches. For a future Sims 5 game I'd like for toddlers and weather to be included in the base game.