I disagree about the extra curriculars…IMHO academics come first and unless you are so talented (sports, theatre, etc) that you could potentially get a full scholarship or it gives you that IVY edge, those things should be what makes you well-rounded without taking away from your GPA (or more importantly, your physical and emotional health).
That being said, I get that each school is different and that every teacher assigns as they see fit but I find it hard to believe that anyone is getting 5-6 hours of homework nightly and if that is the case, someone should be stepping in to assess the reasons why.