You have a point, the front 7 does make the secondary better. However, the secondary is a very talented group. Mike Brown has performed at a very high level since he's been in the league. Neither Tillman or Vasher are "shutdown" corners, but both have exceptional playmaking abilities. Chris Harris is a rookie that is still proving himself, but I've liked what I have seen so far. Tillman,Vasher, and Brown have illustrated their talent in prior seasons, outside of this years dominating defense. The week 11 was definitely a bright spot for the Bears defense, but its not like they went out and sacked opponents QB's 8 times every game. The Bears D doesn't blitz non stop, these DB's deserve much credit in regards to their cover and playmaking skills. I'm not sure if any single DB on the Bears is considered "great", but as a unit, they're one of the best in the league.