If you ignore the know-nothing media narratives and look at the geography of the results and macro-level indicators, it's pretty clear that John Kerry performed about as well as any presidential challenger has in modern political history. He ran a solid campaign.
It's important to remember the dire state of political journalism in the mid-naughts. Nate Silver gets treated as a bit of a punching bag today, sometimes deservedly, but when you look at how elections were covered before 2008... yikes...
I think it's exceedingly likely that Howard Dean would have been a McGovern-tier nominee. He was a poor fit for large parts of the party (and not just the parts that you're thinking of), a sloppy campaigner, and deservedly became a political punchline (albeit not for the right reasons).
Just about his only virtue in 2004 was daring to speak out against US military aggression while stumbling into raising enough funds over the internet that the large media conglomerates complicit in that aggression couldn't ignore him like the other war critics. It didn't take long for them to jump on the first transgression that they could ridicule.
Whenever someone complains about Facebook and Twitter, try to remember what it was like coping with yesteryear's information monopolies. The median voter today is probably crazier, but at least they are divided in their insanity. Unified insanity was why we invaded Iraq, and unified insanity was also why all of the "serious" Democratic presidential hopefuls in 2004 were afraid to openly oppose that invasion.
