Running the ball find a 90 speed 100 ball carry player and if he stays healthy he gets at least 1,500 yards.
I've had success with 82 speed 100 ball carry and even 74 speed with the Tribeca of ball carry, avoid fumble and break tackle.
At CB, I've had success with slower CBs but only if they have 100 m2m and 100 B&R or at least close enough.
Signing older 70 speed CBs with 100s across the board have become solid options too...M2M, B&R, Courage and Zone.
Of course you still want a 90 speed 100 M2M CB to combat the FL hitch even though it's been governed by 4.6.
Bottom line, I still think 90+ speed in overpowered and I've proven that in the Death & Destruction League where I have 40 players on the roster with at least 86 speed and I play an 11 DB defense....to be fair that league has zero injuries which helps but I'm 34-2 through almost 3 seasons