I tend to believe this:
But there are plenty of signs that Team Obama is more than a little preoccupied with Bush — with avoiding his mistakes, reversing his policies in a daily drumbeat of events, and with getting as much political mileage as possible from coded but clear shots at the unpopular ex-president.
The politics of this are pretty simple, I think. People hate Bush, so Obama will try to solidify his public support by repudiating him and his policies while the public's dislike is still strong. The other thing this accomplishes is to reassure Republicans who are justifiably frightened that they will be treated the way they treated Democrats the past 8 years. As the anti-Bush, Obama is saying, "I'm not a vindictive, closeminded asshole like some other Presidents I could name." He doesn't have to say, "who I can hang around your necks if I need to, since it was you assholes who elected him and supported his policies in lockstep."