I really feel in the Sims 4 the babies are lacking. I loved how in the Sims 3 you could move the baby around the house with you, example; you could have a play pen in the living room and move the baby...
As for a visual update, it would be good enough if they would just give atleast some of the babies hair. It's not like every newborn doesn't have a single hair on their head, it's actually the opposite quiet often.