I dunno. Aside from the crazy shit that Trump has been saying, Sanders is the one nominee that I've seen get the most exposure lately. The guy is practically taking Facebook by storm!
And Facebook is hardly representative of the people who get out and vote in a general election. People who think he'd have even a snowball's chance in hell fail to realize just how much of the population identifies as Democrat but has generally conservative positions, but they vote Democrat on a single issue like abortion or gay rights. All the Republican candidate would have to do is run one single ad for six months, consisting of nothing but a quote from his book saying, "I am a democratic socialist," and we would see the Republican, no matter how wingnut loony, sweep 49 states.