I think all three of the players ended up in the roles they were given. Song was always the box to box role while Arteta was the sitting player, it was a misconception from fans that Song was going forward when he wasn't supposed to. Cesc was moved to No.10, that's a managerial decision again. Aaron is another box to box player, the nature of the role means it is for him to judge when to go forward and when to go back, much like a full back. Wenger can only remind him of his main responsibility, which he did, quite publicly.
That being said, he obviously gives players more freedom than other managers, I don't think it's a bad tactic in itself, works great when you have the right players. Not so great when you have idiots.
