Man, who else thought that Rams-Cardinals would be a remotely exciting match five weeks into the season? Also more on the Rams
Titans: 2011 - 18th in yards allowed, 8th in points allowed ; 2012 - 31st in yards allowed, 32nd in yards allowed
Rams: 2011 - 22nd in yards allowed, 26th in points allowed ; 2012 - 14th in yards allowed, 16th in points allowed
Any player changes aside (I largely ignore that stuff), clearly Fisher leaving then Titans and finally ending up on the Rams was an underrated thing. I have given Fisher some flak for his teams' offenses myself, but you have to hand it to the guy, if he gets the St. Louis defense running like the Titans defense did at its best and Bradford gets a little better and stays healthy, the Rams should be headed toward some 11-5+ seasons in the future. Meanwhile the Titans are completely screwed and clearly need a better coach. Now granted last year the D looked good under a new coach, but usually it takes about exactly one extra year for a team to collapse under the weight of a new coach who cannot handle running the team the way it was previously run.
I still think that Fisher is not a fantastic coach, his teams end up with way too much variation between looking awful and amazing season to season, but thank god the Rams did not end up promoting McDaniels to head coach or anything.