With the news that Barack Obama has failed to agree with John McCain on his proposal of a town-hall style debate offer, the revolutionary style of debate will most likely not be seen (in the proposed form) during this campaign cycle. While both campaigns may try to paint different pictures of why the debates failed there is one reason the debates failed: potential advantages.
First, John McCain could only benefit from having these debates with the free-air time it provides and the ability to link himself to any Obama news in the media. McCain has largely been an afterthought in this campaign as "the other guy" overshadowed most times by Barack Obama and Hillary Clinton. Having these debates injects him back into the conversation and helps him compete with Obama who is leagues above him in fund raising prowess.
However Obama knows that when voters come out in November they will either reject Obama or support Obama, McCain will just be the other option. By keeping the focus on him he makes this November vote not an election but a referendum on himself. It will be very interesting to see how this plays out over the next few months.