It is fairly clear to most observers that Arsenal have an issue with defence, especially at centre back but even if they bring in a top-quality central defender it will not necessarily solve the biggest problem that Unai Emery has on his hands.
And that is a leader on the pitch.
Too often certain negative aspects of the Arsenal game creep in, falling back, panic, lack of composure, drop in confidence when a goal goes in etc and the reason that happens so often is because of lack of leadership on the field of play.
A leader does not always have to be a shouter or screamer or that go-to type of character but someone that can lead by example as well, someone that can articulate strategy on the pitch, someone that can motivate and say the right words at the right time.
And the brutal truth is that Arsenal simply does not have that type of player.
There will be dips in form at some point in the season, last season it came at the critical backend and that extra point or two could have been found with the right leader.
So, while a central defender is of crucial importance I would argue that a leader is just as important even if he is not a defender.