I'd guess most mainstream liberals are skeptical about the merits of plebiscite democracy, at least the few I've read on the subject are. And it does correspond well to their general attitude toward the stupidity of the mob rule. The preponderance of anti-gay ballot initiatives and the general political malaise in California are generally cited as examples of where allowing popular votes on policy go awry.
The MA-Sen race, however, provides a pretty good oppositional case against media-managed representative government. Despite the localized nuances of the race and the fact that a not insignificant number of Brown voters were in protest of watered-down healthcare reform and timid policing of Wall Street, the narrative of Brown's win is nonetheless being written to fit the script prepared by the managers of democracy. Choosing between two candidates with purposefully ambiguous policy aims makes it virtually impossible for the public to make concrete political desires manifest.