As far as I know this isn't the first time Arsenal have done it , few seasons ago they did the same but after the middle of the season they lost all power even though they are still playing with the same squad let's see if Arsenal repeat it again.
Not everything has to be the same as last season at Arsenal, because last season there weren't many players who were consistent and productive enough in every game so Arsenal's performances didn't look so consistent last season. Whereas this season I have seen that there has been a slight difference in appearance since the presence of Gabriel Jesus at Arsenal's front line who was very productive using every pass that was aimed at him.
Surprisingly Arsenal did it not once but even many times the difference is sometimes at the beginning of the season sometimes at the end of the season , maybe you remember last season how Arsenal ended the season from the relegation zone ended in 5th. That's why we will wait in the middle of the season how they end this season.