Arteta was ruled out for a significant amount of last season, while playing in front of a patched up and out of form defence. While IMO he's not the greatest DM (though to be fair he acts more as a deep lying playmaker, setting the tempo, keeping possession and quickly transitioning play from defence to attack), he does bring a lot of positives to the team. And it seems a bit unfair to lambast him for our poor defensive performance in the 1st half of last season when he was injured for a lot of it and he wasn't even close to the only poor performer. Santi could barely string a pass together, Ramsey kept losing the ball (when fit, though he wasn't fully fit until Jan), Merts was very poor, Kos injured/playing with an injury, Chambers was an emergency for almost every defensive position ect.