Personally, I don’t think preseason ranking mean much. I don’t think rankings after 17 regular season weeks mean much either. The issue that may be raised is, “Are the Cowboy getting the respect they deserve?” According to Don Banks’s ranking, the Cowboys are 8 overall, and 4th in the NFC behind the Saints, Packers, and Vikings. It is a fair assessment to say that these three teams were at the top of the conference last year and they did not undergo wholesale changes the way the Cardinals have in the last 6 months. So it is fair to have the Cowboys as a top team in the conference, but not necessarily the top team.
The rankings are unimaginative, however. I respect Banks’s opinion, but I find all pigskins prognosticators look at the records from the previous year and copy and paste. The top teams in the AFC in 2008 (Steelers and Titans) both missed the playoffs in 2009; the top three teams from the NFC in 2008 (Giants, Panthers, Falcons) all missed the playoffs in 2009. Certainly with the turnover in playoff teams, it would seem within reason to go out on a limb for up and coming teams like the Niners, Rams, Redskins, etc.
If there is a moral to the story it would be: Sleeping on sleepers will give you a backache.