I think this is a pertinent point, depending how you play 12 has a varied option of strengths.
I personally dont hate the Ford Farell 2 playmakers left and right of the scrum, it offers kicking and ball playing options, and IMO allows eager wingers to play off either sides shoulder.
The problem becomes focus in attack, and ball carrying, imagine being Youngs and both players are demanding the ball, for different reasons, maybe it's a case of too many cooks?
I think 12 takes a bit of time, look at Tompkins, getting plaudits now, but it's been 2 seasons of wild headless chicken play, hes always been a great ball carrier, but he leaves his position in the defensive line, he takes on too much and just constantly over plays.
Against Fiji he gave George North a nightmare, North never knew where he was at any point, for the 2nd try, and the Radrada drop Tompkins didnt enter the line, let alone come off it hard, he corner flagged lol.
He finally looked disciplined against Aus, and it settled our entire backline.
I think maybe that's what England need, just to settle someone in there for a period and let the backline grow as an organism?