Agree. But at the moment, we dont really have a central midfielder capable of holding a four man midfield. No midfielder we have has that presence about them. Arteta has, but he needs a ball winner next to him. Cahill hasn't got enough to his game (in my opinion, hes a supporting striker), Fellaini in a few years maybe...
Thats why we need someone like Lucho Gonzalez (too old now though for the fee he would command), Moutinho.... M'bia maybe (Though he would be the ball winner who allows Arteta to drive forward). Someone who can get hold of the ball and drive it forward - who opposition fear and drop back.