During the last 4 years there have been 26 coaching changes. There will be 7 teams this year alone with a new coach and system. Some teams have had several new coaches within that time period (Arizona, Oakland, Atlanta, Miami). So how does that affect the fantasy aspect and the points those players produce?
Using averages, the quarterback position increases touchdown production but only by about one half per year. The yardage decrease, however, was by over 800 yards per year. It should be noted the horrific season from Alex Smith in 2005 and Aaron Brooks in 2006 lowered those averages considerably. Without those two performances the average would have been one touchdown more per year and 160 more yards.
The running back position saw a more significant increase. The average increase was almost 2 touchdowns higher per year. The increase in yardage was 154 more yards per season. This is most likely attributed to new coaches trying to come in and establish a running game of some kind.
Wide receivers followed the patterns of the quarterback. They scored .5 touchdowns more per year and 47 more yards per season. Again, removing Alex Smith and Aaron Brooks numbers they go up to 2.5 more touchdowns and 113 more yards per season.
Using this information would increase the value of Edgerrin James, Ronnie Brown and LaDainian Tomlinson (can it go any higher?!) It would also suggest Matt Leinart, Tony Romo, and Phillips Rivers should not be expected to produce significantly higher numbers. The same could be said for Larry Fitzgerald, Anquan Boldin, and Terrell Owens.
Each team situation is different and should be considered on a case by case basis. Keep in mind, however, history does tend to repeat itself.