I know this link has been cited before, but the data deserve a closer look
http://people-press.org/2011/08/10/democrats-not-eager-for-an-obama-challenger/?src=prc-headlineLiberal--28/71 against
Conservative/moderate--39/58 against
Independent leaning Dem--47/50 againstClose followers of 2012 candidates--21/70 against
Non-followers of 2012 candidates 40/52 againstDrew Westen was on NPR Friday, and he pointed out that his political consulting business is not about how to appeal to progressive voters, but how to appeal to centrists. And the number one thing centrists want from their president is STRENGTH! They mostly don't know about and could care less about the details of a politician's actual policies.
It is precisely the poorly informed and less liberal who are turning on Obama. These are the folks who stayed home in 2010, not the progressives. Liberals and those who pay close attention are not (in my area at least) any less critical of Obama--we are just more likely to be thinking strategically about the problem of how to both successfully challenge Obama and still win. Not possible, and IMO we ought to be focusing on 2016.