Now that organizations like Khan Academy have traction and resources, I think they'll be able to bridge the gap. They'll be able to iterate as they receive feedback from the educational community.
Instead of viewing mathematics as a series of problems to be solved, each of which has a solution, maybe it would be neat of the Khan Academy actually spoke to some educators (and then publicly announced the results of this consultation)?
Khan Academy is all about computer lessons at home and all the class time devoted to student teacher interaction
The lessons they're learning from the massive amounts data they've been collecting from real students (ones outside the pilot programs, who are using their material in an uncontrolled, natural manner) also shouldn't be discounted, and I would argue that it might be as useful as talking to educators can be. It's definitely a Silicon Valley thing to put data up on a pedestal, but should it be valued any less than education research that can be hard to generalize from due to problems with experimental design (like giving extensive training to teachers in the experimental conditions when it's unlikely that most teachers who'll have to implement the same experimental curriculum will have the same sort of training/enthusiasm) or anecdotal evidence from teachers working with one or two classes?
As to why many people might want to defend Khan Academy, well, its because I think I would have been much happier with Khan Academy than the math education I actually had, and I would very much like it to be available to children like myself. I was bored stiff in math class in middle and high school, and being able to work at my own base, not bound by the slowest person in the class, would have been amazing.
Today at 3:30 I'll be at our Los Altos district teacher feedback session for hours.
As a dev, I meet with our pilot teachers regularly.
Our implementations team does it literally every day.
I have multiple email threads in my inbox of long back-and-forth conversations between our developers and our fearless teachers.
Ok, back to work!