My DS12 has 3-4 hours of homework every night in 7th grade. I totally agree that he should have homework and that about half of it is valuable practice and development of academic skills like writing. But the poor kid comes home from school, grabs a quick snack, does his homework until dinner, finishes his homework, practices his instrument (also homework), takes a shower, and goes to bed. His participation is sports and band at sporting events just means that he's up later and not getting enough sleep. It's no wonder kids today are getting fatter -- they have so little time to be outside getting physical activity and they're not getting enough sleep. Not to mention their lack of time to do creative activities or to explore other areas of interest. Heck, my DS barely has any time to read any non-school books of interest without having to give up valuable sleep!
So, yeah, doing homework teaches him to work hard and organize his time, both of which will be valuable skills in college and in life (Goodness knows it would have been nice if I'd learned to study before college!) but it's all just too much. I wish there was something to be done about it!