In colleges, they use hundreds of teaches that most of them have little to no connections with each other. Teachers teach in different styles in big settings like college and high school. SO communication will be somewhat conflicting. Also there people taking different classes on different days, which would make the process confusing and overly complicated. If the school tries to regulate it, it wont be as effective due to the fact that they have little control on the curriculum used in certain classes.
The best solution I know from experience is to just simply talk to the teacher and explain the situation. Some teachers do care about their students and if they simply ask most teachers will find a way to lessen the load and make it easier for their students. I did, and because of it I only had to do half of the homework, like only the odd numbered questions or got extended due dates on papers. Its less work on the student, as well as the teacher. In conclusion, excessive amounts of homework is a very common problem, but has simple solutions. Teachers can focus on enforcing more in class work to lessen the load on outside homework. Or the school can step in or have a way for teachers to gauge each others amount of homework given. But the best solution is to just simply talk to the teacher