I posted something last offseason showing that the Steelers were averaging about 7 points more per game with Bell out, with a fairly large sample size. They are better when they move on from an old philosophy of overusing the running back position, especially when they have Antonio Brown and other talented receivers. It isn't that hard to figure out...you average about 4 yards when running it and about 6-7 (adjusted for sacks) when passing it. The RB position can be vital in moving the chains, forcing the defense to change its philosophy, and red zone production, but it's not in your best interest to take the ball out of the hands of your above average passing game. There was a stat that Bell didn't get any 30+ yard gains last year, or as Tomlin refers to it "he needs to get more splash plays." How many times does Roethlisberger connect on 30+ yard passes? A lot more than zero times per season.