I don't really have many specific things to say about David Bernstein's rankings of the 2012 GOP contenders, because I generally don't have views on who the Republican Party is going to pick in 2012. It's a chaotic situation, largely because the candidates are pretty bad.
The 2008 Democratic primary was a model of stability. For a very long time, the conventional wisdom was that Hillary, Obama, and Edwards were 1-2-3 with everybody else in a big mess behind them. That stayed pretty stable until Obama slowly pushed ahead over the course of the 2008 contests. Part of the reason for the stability is that (setting aside the ticking scandal bomb attached to Edwards) they were all very good candidates. Other than Al Gore, who made the wise choice not to run and thus maintained the implicit threat of making or breaking a campaign with an endorsement or a curse, there was nobody out there who could upset the order as it was.
It's basically the opposite situation with in the Republican primary. Everybody has some combination of general-election weakness, a very low public profile, or unacceptability to a large portion of the Republican base. The success of a campaign will depend in large part on who else is running and cutting into your territory.
I guess the only direct criticism I'll make of Bernstein is that you can't count Sarah Palin out in a race like this. Since she has a hardcore fanclub that's going to vote for her over anybody in her niche, she can easily be one of the last 4 or 5 candidates standing if she wants to. She'll need lots of luck to get the rest of the way, but so does everybody else at some stage or another.