They don't have a chance otherwise imo. Chris Christie, Rick Santorum, Huntsman, or Jeb Bush or whatever, wouldn't stand a chance against Clinton or Biden (if things improve). IMO a large part of why they lost this time is because once again, they felt that a moderate candidate gave them the best chance. Ron Paul polled better against Obama than other candidates in the primaries and he's consistent. Gary Johnson, Rand Paul too. Libertarians are more appealing to women, certain minority groups, and some Democrats. Unfortunately Republicans are still full of hawks and religious cons so a Libertarian candidate getting nominated next time is very unlikely, but luckily hawks/religious cons are dying breed whereas fiscal conservatism is not.
In any case, everything is bound to get slightly better in 4 years (can't really get any worse), Clinton's name is still strong and Biden can make a case if the Obama administration leaves with positive approval. Another moderate like McCain and Romney won't cut it.
Most Conservatives won't take this seriously and will likely scoff at the notion, while liberals will probably laugh, but to me it seems undeniable that a more libertarian candidate gives the Republican party the better chance. The libertarian candidate doesn't necessarily have to be as extreme as Ron Paul/Johnson, heck Rand Paul has some appealing Libertarian policies to some degree.