I think what Clayton Christensen has contributed in terms of his theory of disruptive innovation at the Harvard program is valuable. An MBA trained under him would have an visionary adavantage in a startup situation.
I have a Harvard MBA and took Christensen's class. The guy has a major outsized ego and frankly I didn't learn much more in his class than I did from his book (other than he's diabetic, Mormon and likes to cold call!).
A friend with a fairly recent MBA from Harvard told me that such professors are highly sought after by students. The school has some sort of lottery/bidding system to allocate slots in those classes.
if Harvard were interested in spreading the good word, they could have taped the lectures and had them online by now. I'm sure you don't need to be in the same physical room to get 90% of the good man's lessons.