John Judis nailed it in his New Republic analysis: It is indeed a political relaignment, the first since 1980, which was the first since 1932. Judis also makes a cogent case for an emerging progressive majority in America's post-industrial society.
So, this is the first part of the answer to the question: What's wrong with West Virginia? And remember, West Virginia once was a reliably Democratic state in any year other than a Republican landslide.
Update: This Charles M. Blow New York Times blogblog. West Virginia didn't matter, as he astutely said last May.