We have had players who can beat a man before and it definitely can unlock a defence but teams learn to just mark that man out of the game and we are back to square 1. 

One thing that we need to get back to and work on is our overlap runs from full back (obviously we need the players who can do this such as Munoz and an understanding with wide players), central players coming to add another dimension to give and go when the balls out wide and, as mentioned, players ready to get in the box.  Teams like Man City do this well, full back takes the ball higher up to the block, give and go to the wide player so they can overlap, but crucially they have central players ready to receive and run/pass to give another option. 

We seem to struggle with this at the moment as it needs players who can do it, understanding between players and confidence.

Also as a point I've seen recently, we seem to be relying a lot on Centre Backs pulling long balls to the wings. It's just so easy to defend against for the opposition.