The former midfielder believes the lack of defensive nous in the side makes them vulnerable against the best sides.
The Gunners are currently missing several key players, as injuries have ravaged their squad, with Aaron Ramsey and Alex Oxlade Chamberlain among a lengthy list of absentees.
Their loss was felt heavily in midweek, as Arsene Wenger’s side were demolished 5-1 by Bayern Munich in the Champions League.
And Souness says a big problem for the north London outfit is that they have several number 10’s, all of whom are too similar, meaning they lack options in the midfield engine room.
“For me, Arsenal have a midfield full of number 10's so when they are on form and boss a game then they look great,” he told Sky Sports.
“But my criticism of Arsenal in the past is that group of midfield players are a bit too similar. Francis Coquelin has come in and given them something a bit different, but we have seen in both matches against Bayern Munich they are lightweight in the midfield department.”
The former midfielder also believes that there is a lack of defensive-minded players in the side, which is another big problem.
Currently they only have Francis Coquelin who can operate in a holding midfield role, and although Santi Cazorla has adapted his defensive game, he is still more of an attack-minded player.
The same can be said of the defence, with the full-backs in particular looking more comfortable going forward than they do being forced onto the back foot.
And Souness believes the midfield’s inability to dig in and nullify opponents makes them vulnerable against the best sides in Europe.
“I would suggest that some of the players in that back four are not the best defenders and the strength of many of those players is going forward,” he added.
“Also, when they are not bossing a game, some of the midfielders allow things to pass them by. They don't dig in and nullify the threat of the opposition and I think that makes them vulnerable against the very best teams.”