It's a topic that has been discussed repeatedly... sometimes by people who understand what they are talking about, and other times by people who just like to make uneducated generalizations.
Enter a couple of guys who know what they are talking about: Doug Farrar and Calvin Johnson.
First, Farrar talks about the Cover-2 defense that the Chicago Bears (along with a few other teams) run. An excerpt:
But as Kiffin has said, “Cover 2 became a lot better when we had better players.” That’s true of any scheme, more so with the Cover/Tampa 2. When the Bucs were killing offenses with it, they had potential Hall of Famers in their front seven (tackle Warren Sapp and linebacker Derrick Brooks whose talents were especially suited to these schemes. Many teams that played copycat without the same talent failed. Dungy’s 2006 Indianapolis Colts team won the Super Bowl despite having one of the worst run defenses of the modern era. That’s another problem with the Cover 2; run support from your safeties can be tough to find without breaking out of the box. Even the post-Dungy Colts are augmenting the front four by going with more blitz looks.
Make sure you click the link for Doug's full analysis. Very, very good stuff there.
And next, Lions WR Calvin Johnson weighs in on facing the Bears defense this weekend in Week 1 of the regular season:
We are familiar with both coordinators. As an offense, we understand what Rod likes to do – he definitely likes his Cover 2 and likes to get pressure with the front four. Hopefully we stop that pressure and we’re able to do what we do on the outside. I think if we’re able to stop the pressure of the front four, they’ll have to bring another man down in the box and we’ll have some one-on-one match-ups on the outside.
When we saw them in preseason we saw a lot of that and Cover 1 and Cover 3 as well. But you never know – we may get lucky and catch a lot of Cover 3. Hopefully we do and we can do some things on the outside.
Do the Bears have the personnel to run their defense effectively this season? We'll see. I know I'm personally not looking forward to Johnson opening weekend.