Sometimes I have observed that Arteta gets into good positions defensively and gets good interceptions, but many times he tries to merely press the opposition player rather than tackle or get stuck in. Against midtable players, this would work as the panic created would force them into poor passes, but against better players and teams he would be easily bypassed.
I am in favour of replacing him with a mobile defenisve midfielder in the first team, but he would most definitely be a tremendous squad player
Its sad that good tacklers have become a scarce commodity.