There is no doubt that there is a need for homework, but perhaps it's not too much homework that's the problem, but just the type of homework. Maybe teachers could be taking advantage of the environment outside of the school to set different homework tasks to enrich the students learning. I'm not saying that all homework should be fun, but a different approach might be in order.
Teachers might think about letting parents come into school to both assist with their child's learning once in a while and to understand how things are taught. How many thrown pencils and temper tantrums between a well-meaning parent and child could be avoided by just having a greater understanding of the teaching practices in school!
Maybe, where possible, more practical homework could be set, with a small write up so teachers know the work has been done. Homework then becomes the child examining the world around them rather than just homework as print on a page -- there is really little need for marking on the teacher's part, too.
An approach I really liked that my daughter's school adopted for weekly homework was that suggestions for study and practice were sent home rather than demands. This not only gave us the whole weekend to complete the work, but really lets the parent be the teacher outside of school -- a parent is likely to know where their child needs most help after all.
Perhaps we might consider the approach of setting 10 minutes of homework per grade per night, as being discussed in the New Jersey region. For a first grader this gets them into the practice of tackling homework without putting them off and is plenty of time for some reading or writing practice. In Singapore there is a particularly strong feeling about this as some first graders are getting around two hours of homework per night. I'd be amazed if my child of the same age would stay awake that long after a day at school, never mind complete the tasks effectively! Do we really want stressed out five and six year olds?
Of course this same practice might also have the effect of clock watching from the child's point of view, or those children that really need the extra time to practice outside of the classroom to fall even further behind. Hmm, I'm beginning to see why this is such a minefield for all of us -- teachers, students and parents on a worldwide scale.
Another approach might be to give the same amount of homework, but more time to complete it in. It's a much more efficient use of time and students are likely to retain more information this way.