I'm really not sure what I'm supposed to be seeing here. Sure there are differences, but nothing that I would call alarming. I took a quick glance before work this morning and a much longer look now that I'm home. All I see is small random variations of the parents features. They aren't clones, but if you put them in a lineup without telling me who was who, I feel certain I could match them to their parents. I like that they're imperfect representations, it makes them uniquely their own selves. The sim genetics for the most part do a good job of picking and combining features from both parents.
The differences I see between your sims and their parents is easily tweaked in CAS if you really want them to be as close as possible to their parents. Enjoy their differences and don't sweat it.
