That come as consequence in my opinion. Playing deep, our defense will be solid, but it has cost on our created chances and goal productivity. Playing high line, we might will be scoring more, but also will leave some empty space on our back when we built our attack. Now the most difficult part, is to determine when to put that strategy right for every single match. Again weak team we could play the high line, but against big clubs away, think we should play more deep. Also no guarantee if we replace all of them we will be solid at the back immediately. Players like Ivan and Cahill are experienced enough, yes maybe they are not the fastest defender in the world, but they can be good if the plan is right.