I hunted high and low and found a close up of a couple of kids from one of my current saves (I tend not to take close ups of kids) and it would seem that their noses are a little beakish :D Although I like to play big families the toddler and child stages really don't interest me and are used only to set up a skill base for the later stages. Because I don't play long life spans I don't mind that the kids aren't especially cute. I just slap on cute hair and clothes and they look fine from the distance I play my sims at.
I would never change a child's genetics for a cuter look. I already know what they will look like as YAs because I always peek when they become toddlers and, as long as I know that they will look better when they grow up, I can put up with the short time they will be kids.
https://live.staticflickr.com/65535/48629329882_f49049ac0a_o.jpgThey are currently teens but this is how they will grow up.
https://live.staticflickr.com/65535/48550327486_0562073e9c_o.jpghttps://live.staticflickr.com/65535/48499856832_9dfebc3750_o.jpg