I now have a child in her second year of college, another who is graduating high school this year and one who is in his last year of elementary school. So I've seen the end result for my own kids with high workloads.
When we first transferred into this district, I resented the work load that the teachers put on the kids. But after we adjusted, I've seen some benefits as well.
My kids took a lot of AP (advanced placement) classes in high school which allowed them to test out of the correlating college class if they could pass the test at the end of the year. My son's homework load has been brutal at times - 5 to 6 hours some nights, because he took especially challenging classes, but it has taught him to be efficient, use his time in class wisely, and develop a work ethic (something I thought would take a miracle when he was in mid-school).
We also required our kids to take some type of music instruction in the instrument of their choice up until high school and to participate in one sport, also of their choice. My son was in the marching band through his freshman year, and it was the band instructor who made it too difficult to continue by demanding that my son choose every band practice over sports. So my son quit. Both my older kids chose climbing as their sport and took it very seriously.
The benefit has been that they were too busy to get into trouble during those difficult mid-school and high school years and that we always knew where they were. Their teammates became their friends, and most weekends were spent outside climbing in some remote area of the state - something I was happy to support and encourage. And best of all, college has been an easy transition. My daughter is used to the work load and went in with many of her core classes already credited to her transcript from her high school AP placement tests.
So yes, the homework does dig a bit into family and fun time. But it has also had its benefits.