Obama’s not crazy, and so he’s not going accept this, which is something that plays more to McCain’s strengths than his own. He’s proposed a series of “Lincoln-Douglas”-style debates. Considering that the originals were essentially a series of dueling (and quite long) speeches, that’s right in Obama’s wheelhouse, and thus not something McCain would ever agree to.
Basically, what Obama needs to do is find a format that maximizes (a) the direct interaction between the candidates, and (b) the length of time each candidate speaks in each segment. McCain wants to find a way to make things as freestyle as possible with interaction with the public, because he’s good at that but a terrible speaker.
It may not matter. There are a lot of ways to go wrong predicting what the American electorate will do, but they’re pretty consistent in choosing whoever looks the best on TV. Since 1960, they’ve done this every time with the possible exception of 1968 (I don’t know enough about Humphrey to judge). And Obama is much better TV than McCain except in a comedy sense.