Really interesting article about the Gates-funded school that you linked. I read about a similar approach used in the UK about...30? years ago. It is one way to do it, definitely.
Running, you bring up a good point about freedom. I know a lot of people who would have been better served by leaving HS to go do something worthwhile with their time. But what about basic skills, such as reading and simple math? Even in today's "I do what the TV tells me!" era of information, I think reading is fundamental to participating as a full citizen. At what age should the choice be offered to the child, or are you speaking of the parents' right to pull the kid out of public school and initiate homeschool/votech/private without complaint? I think I'm misreading you or I'm being too literal.
(And to answer a question, I'm debating going out into the world to teach and also worrying about what my young family members are going through.)