Khan Academy is videos of lectures. This is nothing new. They are boring and do not allow the student to interact with the lecturer. They also focus on solving a math or science problem through basic steps, but do not focus on the actual theory behind the problem. The student may be able to solve that problem, but can they apply the concept to other problems and situations?
But a lecture is a lecture. The teaching limitations of delivered information are inherent and familiar to all experienced teachers who pay attention. Flipping classrooms will hardly make a dent in education's most intractable problems. The idea doesn't even come close to meriting the over-the-top head that Time's editors gave the article: "Reboot the School."
Intractable educational problems will begin to disappear when learners' rear ends are gotten off school furniture and allowed out where life is being lived, when learners' eyes are lifted from reference works passed off as textbooks and directed to the real world, when learners' minds are respected too much to treat them as mere storage units for secondhand, bureaucratically selected information.
Intractable problems in education will begin to disappear when kids are not just allowed to chart their own course, but are encouraged to do so, and given means to that end. Too bad there are no policymakers willing to promote that idea, and no rich philanthropists willing to put up encouragement money.