I'm gonna treat this as a 4-3 defense
QB- Packers, Bears, Lions, Vikings
RB- Vikings, Lions, Bears, Packers (I think GB has better depth than the Bears but Grant was pretty bad last year so I'll just leave it as is until he improves.)
FB- Packers, Vikings, Bears, Lions (TBH I know little about this position on the other teams)
WR- Packers, Lions, Vikings, Bears
TE- Packers, Vikings, Bears, Lions
OT- Vikings, Packers, Bears, Lions
OG- Vikings, Packers, Bears, Lions
OC- Packers, Bears, Lions, Vikings
DT- Vikings, Bears, Packers, Lions
DE- Packers, Vikings, Bears, Lions
OLB- Lions, Bears, Vikings, Packers
MLB/ILB- Bears, Packers, Vikings, Lions
CB- Packers, Vikings, Bears, Lions
S- Packers, Vikings, Lions, Bears
K- Lions, Bears, Vikings, Packers
P- Vikings, Bears, Lions, Packers
QB and Defensive Line have the greatest importance in the division IMO