Part of the problem is that doing a decent MOOC takes a TON of preparation and effort, much more so than a regular class. The professor who runs the class (Stratos Idreos) has a billion things that he's working on, so turning it unto a MOOC would require some outside support, probably. That said, releasing the videos might be a possibility, I'll ask and see. I believe Andy Pavlo's class has videos online already.

The other part is that in the Harvard classes specifically, the class discussion is a huge part of the class.