Every move made by a coach brings advantages and disadvantages. Every move is an exchange. It is to be hoped that the exchange brings about a net advantage, but every move has a cost.
Take the likely move to 3-4. While any defensive coordinator can run a 3-4 or a 4-3, it continues to look probable that we are looking at a 3-4 for 2009. To me, it isn't so much because of "who" we are bringing in, but because of statements they have made, as well as our present situation (weakness on the line, strength at LB).
The biggest issue for the coaches and management will be in two parts.
1) a 3-4 just doesn't work uness you have a star quality NT. (In theory, a team can have two star quality DEs instead. But this really hasn't translated to the field in the NFL).
2) From a draft and FA perspective, LBs are easier to obtain than DLmen. NTs are very rare finds.
Denver has some clear advantages and disadvantages moving forward. Let's take a look at them...
NT - The Achilles Heel of the 3-4
If the Broncos move to a 3-4, they will have to bring in a substantial presence at the NT position. The NT becomes something of a quarterback for the defense; none of the other positions matter if you don't have a superior player at this position.
What does this mean going forward? It means that, until the Broncos obtain that key piece, much of Denver's moves in the reloading season become tied up until the NT problem is solved. In a 4-3 the MLB is often seen as a key piece, but the weight of the team can be more evenly distrbuted. Not so for a 3-4.
Denver will also need a back-up. Like the QB position, one can't expect the back-up to have as much quality as the starter. But he at least needs to hold his own for at least a few plays here and there.
Unlike the 4-3 where any player can be injured without too much loss of talent, a 3-4 team can suffer terribly if the starting NT is lost for more than one game. The NT is like the queen in chess; she's so powerful that she can be a hinderance because her loss can have such a negative impact.
A lot of money will also be tied up in the position.
3-4 advantages (in Denver's case)
On the other hand, once a good NT is found, Denver may be in terrific shape. The LBs don't need to be as talented as many of the 4-3 LBs are in other schemes, mainly because there is an extra LB on the field.
Denver has several LBs that fans have gravitated towards (Woodyard, Williams, and hybrid FB/LB Larsen). If Webster, K2, and even Bailey are dropped, the team doesn't have to obtain a superstar to fill a fourth LB position.
At DE, Denver (depending on system) can use run blocking DEs (or any former DT) at DE, or go after talented one gap rushers who will combine with the OLBs for advantages on the edge of the OL. I think Denver can fill the DE position much easier with the current roster for 3-4 than they can with the 4-3.
Thoughts on DL Versus OL Match-ups
Consider a few ideas about how lines match up. Because of rules on what a DL can do (as opposed to what an OL can do), it is a common idea that one DLman is worth 1.5 OLmen in a pass rush. If you have 4 DLmen, they outnumber the 5 OLmen 6 to 5. Given enough time (a few seconds), the DLmen will always get to the passer.
To counter this, offenses either pass the ball quickly, or pull in more protection (such as a TE or RB).
In moving to a 3-4, we will also be commiting to rushing at least one LB each pass play. The advantage in a 3-4 is that the offense won't know where the fourth rusher is coming from. Because the rushes often come from the OLBs (in the 3-4), TEs are used more to block than RBs. Two TE sets are the common pass protection formations against the 3-4.
Against teams with fast RBs, the wide alingment of the OLBs will help to negate wide rushes. On the other hand, power runs up the middle will be hard to defend against because the LBs lose the protection of one DLman.
This is why the NT is critical. He must be superior, and worth 2 OLmen instead of 1.5. He must demand double teams on every play, but have the stamina to stay on the field.
What Kind of Defense Can We Expect From a 3-4 in '09?
IF Denver moves to a 3-4, there are three likely forms it could take. It is still too ealry to be sure we will use the 3-4 as a base formation, and still too early to tell which system could be run. However, most 3-4s have a few things in common.
Most 3-4s feature a more aggressive posture against the QB. Denver fans dissapointed with the multiple 3 man rushes in 2008 will enjoy more pressure on opposing QBs.
3-4s are also more enjoyable to watch. Whether the formation is part of a power scheme or a finesse scheme, more players are out of the trench (few fans enjoy watching the lines) to watch the game. Even the rushing "4th LB" looks like a blitzer to the average fan. While a few seasoned fans may enjoy watching the trenches, there is more action in the midfield for the majority of football fans to watch.
Because LBs are easier to find (and finance) than DLs, fans will also enjoy the excitement of following four LB players instead of just three. Outside of the difficult NT position, a 3-4 is easier to put together than a 4-3. (In my mind, the NT position balances out the difficulty. Once the NT is found, the rest of management's job is all downhill).
In sum, if Denver switches to a 3-4 then the NT is the key. Once that key is accomplished, Denver will have a terrific defense. Without that key, Denver will remain in the wilderness for some time on defense.