I've been incredibly underwhelmed by the various arguments that Obama just isn't sending the right message--he isn't populist enough, or he didn't push for a larger stimulus or a public option, or whatever it is the writer wishes he had done . . . and frankly, probably wishes he had done whether or not this improved the party's electoral fortunes.
Most of these analyses border on the frankly incredible. In the world of these writers, there was some hidden pocket of senators who could have been overcome had Obama simply unleashed his fierce presidential will. In the world I live in, the administration got as much stimulus as it was going to get, against a population that was tepid and a bunch of senators who were timid. He was limited on housing relief by homeowners and renters who weren't in trouble, and resented giving their money to people who had bought too much house. He in fact scored some major legislative victories, like health care, against fierce headwinds. The only place you could argue that he had more room was on a more bank-punitive bailout, and subsequent financial reform packages--but in those cases, the technocrats at Treasury had reasonable fears that this would have caused credit markets to contract even more severely, with the resulting economic decline making Democratic poll numbers even worse.
I think it's possible that the Democrats would now be in a better position if they had underpromised. Instead of framing the decline as a Bush-caused disaster that they could fix, they could have said that financial crises are multi-causal and take a really long time to fix, and that it was therefore going to get worse before it got better. Obama did make a few noises along this line, but mostly he followed the line of blaming Bush, and promising dramatic relief with his policies. Since the dramatic relief has not arrived, voters are naturally going to be skeptical of his policies.