Children need space as they grow up and with children entering puberty and adolescence. Teens gets stressed more easily and with everything at school and homework they need time and space to relax. Free time also makes people happier so with more free time they will be happier for when they are at school
Short version: Children need less HW and more time outside. 2x child obesity rate, 4x teen obesity rate.
Medium version: Kids already have way too much Hw, so much that its having a negative psychological effect on us students. We should get dramatically less HW, but less screen-time as well. Kids and teens, especially teens, need to spend more time outside to stay fit, and American obesity is now worse than ever! "Childhood obesity has more than doubled in children and quadrupled in adolescents in the past 30 years. The percentage of children aged 6–11 years in the United States who were obese increased from 7% in 1980 to nearly 18% in 2012." (http://www.Cdc.Gov/healthyschools/obesity/facts.Htm)
Long version: There isn't one because I'm supposed to be doing an AR test in school for gosh sakes!
I agree that homework is crucial, but play is just as important. And when parents say that kids need to boost their grade, or to get straight A's, it actually puts a lot of stress on those children. So when kids spend all night doing their homework, and they go to school with a really bad attitude, and gets suspended, they can just blame their parents. They made them stay up all night studying, so they didn't get any sleep. And a child's parents should know that sleep is important, so when they fail an assignment it's gonna be their fault.
Children these days are so busy that it seems like they never have time for anything. They have homework, soccer practice, ballet and piano lessons. They need more free time to play. Play is very important and is often overlooked. Parents want their children to be more successful than their peers. This drive often makes children miss out on play!
If this question is insinuating that the school schedule should become more lighter and less time in the classroom, the no. Kids are only in school roughly for 7 hours a day, and they are usually free to around 3:30 in the afternoon. That gives them plenty of free time left over from the day.