In my experience, Ron inspires far more wide-ranging actual admiration and affection from people who don’t agree with his whole message than does his son. (See center-left-leaning men’s mag Esquire on how “it’s impossible to not like Ron Paul” and Paul as a top-10 congressman.) Ron’s ability to stress that military spending should be first on the budget chopping block before government spending that fills the pockets of the less well off should also help him escape the “evil Republican” trap if he’s reaching out beyond GOP faithful for support. Rand, for whatever reason, has not shown any crossover appeal that I’ve seen.
We’re talking about two different things here. Doherty is focusing on the ability make libertarianism appealing to people across the political spectrum. I’d agree that Ron Paul does a better job at that. I’m talking about the ability to win Republican primaries. I think Rand Paul is a better fit for that. Certainly, all of the things Doherty mentions as Ron’s assets are liabilities with the Republican primary electorate.
Doherty also argues that Rand would be as likely as his father to getted bogged down into the theoretical weeds of libertarianism, citing the Civil Rights Act controversy. But it seems to me that this was a one-off and there are many other counterexamples, like his refusal to get baited into a debate over blowback. My guess is the lessons learned from both examples will reinforce this tendency. That said, I personally don’t disagree with Doherty’s final sentence.