Yes, balance. 8 hours per day is enough for children. They don't need 8 plus 3 additional at home.
Jobs today require a lot more learning than jobs of yesteryear. Concentrate on teaching them skills they will need to earn their daily bread. Lots of math, practical skills like wiring, how to invest their 401k, and such. There is just too much to learn today job related to force children to also learn non job related subjects.
Those who are interested in memorizing long lists of state capitals can study it on their own. Lots of public libraries, and free courses on the Internet to teach such things.
If job skills didn't take so many extra hours to learn today, they could still teach the others in a reasonable balanced amount of time. It doesn't matter if an electrician can recite long lists of French kings, it only matters if an electrician can safely wire a house or factory. It takes lots and lots of hours to learn how to safely do electricity, and even more to safely do surgery.