Obama has a simple problem. If he were running the way he is now, during the Dem primaries, Hillary would be their nominee, while McCain would have still been the GOP nominee. Obama, in his haste to offend the least amount of people (demonstrated so transparently during the pseudo-debate), is alienating a huge throng of those that supported his "change" mantra, Not everyone of course, there are the die-hard swooning Obama Cool-aide drinkers, and of course the contingent of toe-tag anyone but a Republican, but for those numerous fence sitters, and moderates who may dislike both parties, are likely to be much more flustered by Obama's lack of conviction & focus, with this effort to try and placate/appease everyone, than McCain's damn the torpedoes, this is what I believe, or this is why I changed my mind on a prior position, approach
And, for the record, Biden was a good choice for veep, IMHO....it just simply negates the whole "change" approach during the campaign, however. It was a political choice vs a choice of "change". A choice that could have really righted that ship, but now it simply reinforces that much more of the typical politician most of the rest of us already knew he was