Well, the author's not voting for Rudy...and I'm not voting for Rudy...and there seems to be quite a few who aren't going to vote for Rudy. He's going to have to pull quite a few democrat voters to make up for the conservatives he's not going to have voting for him.
If ANY candidate is portrayed as too left or too right in the general election, they will loose, unless the opponent is sooo incompetent and disliked that even their side doesn't turn out to support them (think Carter). Reagan won not only because conservatives loved him, but because even liberals had had enough of Jimmy.
You gain the love of your party in the primaries. If your party isn't fractured, if you win big in the primaries, the base is settled and you go after the middle 1/3. If you win the primaries by default (like when you are President) or if the primaries are contentious, you'd BETTER be "middle-of-the-road" or you stand NO chance of winning.
Since we have no beloved, popular conservative running for President the ONLY choice the Republican party has is to run someone who will get a bunch of Republican votes, a lot of middle voters, and some disenchanted Democrats. Just as disenchanted Republican's would not vote for Hillary, they just wouldn't vote, unhappy Dems would not vote for a Duncan or a Gingrich, but some might vote for a Rudy.
I wish there was a Reagan waiting in the wings, but understand, Reagan wasn't a surprise. He had run 4 years before and almost won the primary. We have no one in that position now. Under normal circumstances it would be the current Vice President, but Cheney isn't running. Neither is Rice, or anyone else associated with the current administration. Rudy is the best known, best respected, Republican (in name only) willing to run. If he is not nominated, it will be difficult for who ever is nominated to win.
Damned if you do...