In theory, this system sounds perfect, but I think many of us on CD have tunnel vision. Many, if not most people aren't as drawn to learning for the sake of learning, and these are the people who won't listen to lectures online, and won't do anything in class. Atleast before they got some instruction in class. The other issue is the length. While I do have 2-3 hours of homework a night, I don't expect 45 minutes from each class. If the lectures are online, I absolutely must watch 6 hours of content per evening. Thats a lot of time. A hybrid, in which small lessons are taught in class, to keep the online ones short, would be optimum.
However, for those who do like this approach, and whos schools don't offer it, I highly suggest
Khan Academy. It was founded by a man named Saul Khan, who's mission is to make knowledge available to anyone and everyone. However, for those who it is already available to (us), it is a fantastic way to learn something your teacher didn't teach or review for a test.