Arsenal are often inconsistent, it's a problem they have to fix. This team used to be really able to perform consistently, as evidenced by a brilliant record that was very difficult to do. Yes they have won a season unbeaten record. But that happened a few years ago, it should be a motivation for the management, coaches and players to make their performances even better.
If you look at the team's performance this season for Arsenal, it's been a bit good, but it's still not enough to compete with other big teams in any game.
But Arsenal still have time to change and improve things now or before next season starts, because without changes from now on, it will always be difficult to get good performances.