It's definitely that, we haven't worked out how to cover and when you have Xhaka and Zinchenko regularly giving the ball away, plus of course no left back and an RB who likes to get forward (about which i have no problelm per se), it's asking for trouble
all of it really comes down to Arteta's obsession with certain players and only playing one way - very few teams can always play the same way and still succeed in imposing themselves on any team, regardless of its tactics - we aren't there yet and may never be - I'd like to see a bit more variation and adaptaion, both in our starting lineups and in-game approach