Offensively, the 2007 Cardinals are 16th in total offense. The 2006 Cardinals were... 18th in total offense. The biggest improvement on that side of the ball has come in actually scoring. The Cards this season are 9th in scoring offense, while last season they were 19th.
Defensively, the 2007 Cardinals are 14th in total defense. The 2006 Cardinals were 29th in total defense. In scoring defense, the Cards moved from 29th in 2006 to 23rd in 2007.
The main improvement this season is obviously that the Cards are much, much better at punching the ball in from the red zone. Otherwise, nothing much has changed, and "discipline" is much, much worse.
Is it possible that the main difference in the W/L column that this team is playing a Charmin-soft schedule? Last year, they played the AFC West (where every team but the Raiders was in the playoff hunt), the NFC North (Green Bay was average, at least), and at-large games against Dallas and Atlanta. This year they play the AFC North (with one good team in Pittsburgh and two bad ones in Bmore and Cincy) and the NFC South (which lacks even a good team). Not to mention that the NFC West is as weak as it's ever been.