Whatever shortcomings Paul and his friends might have, Paul's dogma generally renders those shortcomings irrelevant. He is a true ideologue in that his personal preferences are secondary to his philosophical principles. When asked what his position is, he generally responds that his position can be deduced from the text of the Constitution. Of course, that's not as dispositive as he thinks it is. But you get the point.
As for Huckabee - as with most politicians, alas - his personal preferences matter enormously because, ultimately, they're the only things that can be relied on to constrain him.
In this respect, Huckabee's philosophy is conventionally liberal, or progressive. What he wants government to do certainly differs in important respects from what Hillary Clinton wants, but the limits he would place on governmental do-goodery are primarily tactical or practical, not philosophical or constitutional. This isn't to say he - or Hillary - is a would-be tyrant, but simply to note that the progressive notion of the state as a loving, caring parent is becoming a bipartisan affair.
Indeed, Huckabee represents the latest attempt to make conservatism more popular. Contrary to the conventional belief that Republicans need to drop their opposition to abortion, gay marriage and the like in order to be popular, Huckabee understands that the unpopular stuff is the economic libertarianism: free trade and smaller government. That's why we're seeing a rise in economic populism on the right married to a culturally conservative populism. Huckabee is the bastard child of Lou Dobbs and Pat Robertson.
Historically, the conservative movement benefited from the tension between libertarianism and cultural traditionalism. This tension - and the effort to reconcile it under the name "fusionism" - has been mischaracterized as a battle between right-wing factions when it's really a conflict that runs through the heart of every conservative. We all have little Mike Huckabees and Ron Pauls sitting on our shoulders. Neither is always right, but both should be listened to.
I would not vote for Paul mostly because I think his foreign policy would be disastrous (Also, he'd lose in a rout not seen since Bambi versus Godzilla). But there's something weird going on when Paul, the small-government constitutionalist, is considered the extremist in the Republican Party, while Huckabee, the statist, is the lovable underdog. It's even weirder because it's probably true: Huckabee is much closer to the mainstream. And that's what scares me about Huckabee and the mainstream alike.