They [Teachers] took a fundamentally dehumanizing experience - 30 kids with their fingers on their lips, not allowed to interact with each other. A teacher, no matter how good, has to give this one size fits all lecture to 30 students - blank faces, slightly antagonistic - and now its a human experience. Now they are actually interacting with each other.
Taken from Sal Khan's TED Talk (starting at roughly 7:00).
I take major issue with the implication that no matter how good a teacher is he or she must lecture to their students. Being good has nothing to do with it. Its a matter of philosophy and approach. Its a matter of implementing best practice, which should involve as little lecturing as possible. Lectures are dehumanizing when the target audience is 30. How much more so is a video that is targeted at thousands or millions? Where is the ability to adapt to student needs? Where is the ability for students to ask questions?
The Khan Academy might be an improvement over teachers who don't teach (they lecture), but lets not pretend that a 20 minute video has created a sense of humanity in the classroom. Lets not pretend that videos watched at home allow students to talk and work together in class. It is the teacher who must realize that their time spent with students is best spent actually talking with and listening to students not talking at students from the front of the room.
I am not of the opinion that Sal Khan has it all wrong, but I think his perspective is skewed. He sounds a bit like Al Gore claiming he invented the internet. Sal Khan did not invent or allow the creation of a personal classroom he created a set of (boring) videos.