You put way too much faith in kids' desire to learn and their ability to make responsible choices.

> Homework should be optional material for self study, evaluated by teachers if you choose to do it but never forced.

My wife is a teacher and her school does this. The result is that nobody does homework. The kids who need the extra practice don't get it and they fall into a spiral of failure and apathy. This is especially bad for subjects like math that build on themselves.

IMO the better solution is to require and grade shorter homework and provide students with optional, supplementary assignments that can be used to make up for missed credit on homework for the same material. That way students who grasp the material quickly can demonstrate and move on while others who need practice are naturally encouraged to get it without being permanently punished for struggling initially.