With Arsenal's history of defensive weakness, does it indicate we need stronger coaching focused on defense? Should there be a new co-manager who is strong in coaching defense to work with Unai Emery? One person responsible for setting up a new program, new drills, reviewing personnel?
There a many aspects to why our defense is questionable at times.
We have several cases of players making individual mistakes. David Luiz and Xhaka spring to mind lately with the penalties they caused. No amount of coahing eliminates that. It is unthinkable that they have not had coaches throughout their career repeatedly talking about not making THOSE kind of errors.
Then we have the issues like with tottenhams first goal. Xhaka goes up and tries to win an arial duel in midfield, as he should. He loses that one. Problem is that Sokratis somehow decides that he ALSO should go into the same duel as well. Sokratis is late and has no chance to win the duel, the ball is then headed towards our goal. If Sokratis had remained in his positition, the ball would have been his. Sokratis then runs back and looks at the ball, missing Eriksson running on his side, and when Leno can´t hold the ball, Eriksen is first to react and Sokratis watches. Sokratis should not have been ballwatching, David Luiz was closer to the ball. This goal came from mistakes from bad positioning, ballwatching, not tracking or marking runners etc. Those are things players are told about all the time I would imagine, and yet these experienced players made these mistakes.
Both of these example highlightes the lack of decision making. A coach can tell you what you should decide in each situation, but he is unable to control the players decision making process in the heat of battle.
There are tactical sides to our defending as well, but to me it is mostly a player thing. I can many times feel surprised when we let in a goal. It feels too easy, is often a player mistake, and the flow of the game has not indicated that we are in any danger.
And if you have professional footballs coaches who spend hours every day with the players, I just can´t see how they do not adress these issues. To me it must be a player thing mainly.