This is a couple of weeks old, but still basically applies
Johnson (who, as of right now, I plan to vote for) is a much like a classical libertarian (neoliberal economically and liberal socially) but he's not quite as "out there" as the Ron Pauls of the world. He famously said during the Libertarian debates that a Jewish baker should be forced to bake a Nazi cake, but he was really just coming out in favor of the proposition that people ought to follow non-discrimination laws.
He was also a (Republican) popular two-term governor in a purple state loaded with Latinos.
Moreover, the Libertarian party has nominated a solid, respected relatively centrist VP candidate in former Massachusetts Governor Bill Weld. There's a Republican who was moderate enough to be elected twice to the governorship of the bluest state in the country (or just about the bluest) and to anger Republican Senate Foreign Relations committee Chairman Jesse Helms enough to have Helms block his ambassadorship nomination (to Mexico, ironically).
He needs to poll at 15% to get into the presidential debates, but if he can clear that threshold (and "undecideds in recent presidential polls have been close to 15% ), he'll be the only sane person on the stage not named Hillary Clinton.
Granted, Johnson's tax plan is a little crazy, as is his promise to slash entitlements, but he won't actually get them passed anyway.