spot on.
he's a controller, not a tackler. which is why when he's played in the DM role he's average.
when he's playing next to a DM he's excellent i.e. the season before last. when he's the DM and expected to throw his body about, make tackles etc, he's useless. you might not need a destroyer but you need a level of aggression to ensure the midfield isn't overpowered. with arteta you dont get that feeling.
buy a DM, stick arteta next to him and watch him flourish again. but as the kingpin of our midfield? do me a favour.