I'm not sure I entirely agree with you.
Obviously there is synergy between defense and offense. Bill Belichick's defense on the NY Giants in 1991 benefitted tremendously from a ball control offense which killed the clock and wore down opposing teams.
The 2004 Patriots offense may have lacked a bit of the explosive firepower which Brady has with Welker and Moss, but it was very balanced with a tremendous power running game. I haven't seen that balanced an offense since then, and the lack of a running game in the clutch clearly hurt us in the 2008 superbowl. I hope that last year's success with RB by committee plus the addition of Taylor will continue the trend back towards a more balanced offense. I see the rebuilding of the defense as a similar trend back towards the glory years. Regardless of the numbers put up by last year's defense, the fact is that our red zone and third down defense was extremely poor, and we could not make the key stops when we needed to - something which was a hallmark of the SB teams. That inability cost us a SB trip in 2006, a SB victory in 2007, and at the very least a playoff trip last year.
Using the Colts as an example does not inspire me with confidence, as we proved over and over that a predominantly offense oriented team was no match for a more balanced team with a superior defense.
But the point of the Colts comparison is that this is NOT a barren, flimsy, Colts Defense, at all. Just that it does also have the Colt-like awesome Offense, in ADDITION.
The Defensive line is the best 3-4 in the league and among the best 4-3 as well.
Mayo and AD are proven superb LBs. Woods, Guyton are works in progress, that are at least adequate; as is TBC. Crabel is a high draft pick that may develop and shine.
The DBs are not a poor collection. The CB position is loaded with good, fast, quick youngsters and solid vets. The Safeties are more than adequate, even with out the draft. Meriwether is a rising star, and Sanders is a proven better-than-average starter, despite some daft opinions here.
There is no question that This 2009 Defense is the fastest that Bill Belichick has fielded with the Patriots, bar none.
The only question is the pass rush and even without the draft help that we all expect, I am not unconvinced that it will not be fine. It is at least equal to an 11-5 2008 edition, and adequate with the talent already assembled; and may be very good.
The coaches say Woods best game is pass rushing, but in the few starts he had, we haven't seen it yet. Crabel was a high pick, red-shirted to beef up. Who knows what he will produce, but we do know that BB was going to draft him in the second round, and still got him in the early third, after trading with SD. TBC has been good for as many sacks every year, as Vrabel had last season.
Last year's Top Ten is this year's Top Five.