Lew, I believe Dean was also better than the mainstream Dems and even GOP on gun rights. He was harshly criticized for saying that states should have their own gun laws, and Vermont, perhaps the state that respects the right to bear arms better than any other, should be free to enjoy its low crime rates without federal interference.
The mainstream political pundits, including many liberals, attacked Dean for being too far to the Left. Well, in many ways that he swung that way, he was also swinging our way (civil liberties, Iraq war, balanced budgets etc.). Sure, he did advocate universal health care. But the way things are going under Republicans, I'm not so sure that GOP "capitalist" healthcare is much better.
Dean was attacked as unwinnable because he was winnable. Paleoconservatives, many moderates and libertarians would have much more likely voted Dean than Kerry. Conservatives who would prefer Kerry over Dean are the nationalist, pro-war conservatives. Those that would prefer Dean would likely do so not for all that socialist healthcare nonsense, but because of the war, civil liberties, federalism and fiscal sanity.