Performances have improved since Arteta's appointment as manager.
But Arshavin wants to see the Spaniard strengthen his defence when the transfer window opens.
"For me, Arsenal's squad is not balanced," said the Russian. "Offensively-wise they are very good and in attack, they play very pretty football.
"It's good to watch. But defensively – even in my period – Arsenal is weak.
"Sometimes that is down to injuries and sometimes they don't have enough experience but I don't know why this doesn't change."