the defense was ranked dead last in the league that season...but I agree with you that you cant always tell everything by looking at statistical rankings in a vacuum
http://sports.espn.go.com/nfl/statis...on=2&year=2006
defense and special teams were obviously a big part of their turnaround from 0-5 that season, but VY setting rookie records and leading comebacks was a big part as well. He brought a lot of energy and national attention to the franchise. The new energy made quite a difference in contrast to the vibe that the franchise had the year before, and was a major factor in the turnaround (as well as the gradual improvement of the defense throughout the season of course, and like you said, the special teams)