#CrazyIdea: paternalistic surnames are unfair, and perpetuate the idea that a man "owns" the wife and children. They also get clumsy for less common/more complex relationships. For me personally, I'm more than happy with the traditional approach. But if I were to design an equitable society, I think a different approach would be better. Here are three ideas:
1. Maternal line: spouses retain the surnames. Children get the surname of their mother. Easier to be sure of the mother's identity than the father's, after all. Note that this does get more complex in cases of donated eggs or surrogate mothers.
2. New surnames: upon marriage, all spouses decide on a new surname - perhaps honoring some ancestor or picking an aspirational word. Their children have the new surname.
3. No surnames: delete the concept of a family name. People can still have three names, but the last name is just like the first or middle name - perhaps chosen by the parents at birth, or perhaps chosen by the child later.
Side note: it's odd that parents choose the name a child is saddled with for their entire lifetime. Parents don't own the child; they should be able to establish their own identity. Perhaps parents should give children two names and the child picks a third (first) name upon majority, so Francine Smith could become Emma Francine Smith at 18.