#3 No defensive structure
Arsenal signed David Luiz and Kieran Tierney in the summer of 2019 in an attempt to bolster the defence, and though it was obvious the two wouldn't have had a massive impact on the team suddenly, the fans and the board expected some improvement from last season. Fun fact, Arsenal conceded 13 goals and had a GD of 11 after matchday 11 last season, compared to 15 goals conceded and a GD of 1 this season.
With more options for Unai Emery in the back-line, the coach was expected to have more defensive organisation and a better away record this year, considering how ruthless Arsenal were in buying the players he wanted. However, it has all gone downhill for Arsenal this season.
The lack of defensive structure is a mixture of three things; no protection for the back four, players struggling to play in a high line, and terrible positioning by the defenders and midfielders when the team gets caught on counters. Arsenal are conceding 16.3 shots per ninety minutes, which is their worst tally in over five years.
The Gunners have the 13th most valuable squad in world football, which tells us there isn't a shortage of talent, but Emery has failed to deploy a system which would help get the best out of each one of them.
It's still early in the season, and by the looks of it, the board aren't looking for replacements just yet, but Emery needs to step up show some tactical nous to get Arsenal out of this vacuum, which he is very capable of doing.