The truth is that in politics, conventional wisdom is almost always wrong, or at least not completely true. For example, the "running mates don't matter" meme is wrong when it's expressed as "they never matter." Sometimes they do (LBJ and Texas in 1960) and sometimes they don't(2008 and Joe who?) Can you salvage an inferior candidate with a running mate pick? No(McCain/Palin, 2008). Can a runningmate be used for a campaign correction course? Yes(2012).
I think Kristol is also right on "it's the economy stupid." That Carvillian statement is simplistic by design and it was never completely true. "Read my lips..." had as much to do with Bill Clinton defeating H.W. as the economy did. Perhaps "It's always at least partially the economy, stupid," might be closer to reality.
There is one piece of conventional wisdom to which I do subscribe. Voters want leaders. Say what you will, FDR was a leader. Doesn't mean you liked where he led the country but he was a leader. Same for JFK and Ronald Reagan. George W. Bush seemed to have the leadership mojo but also seemingly lost it shortly after being re-elected. If conservatives had any uncertainty about Mitt Romney it was whether he was a true leader. As contradictory as it seems, selecting Paul Ryan to lead the messaging convinced many Romney is a leader. But it goes to Kristol's point. It accomplished that because he was willing to buck conventional wisdom when it appeared he was about to cave to it.