Now Arsenal's players are good, their rhythm is also good and Havertz can still develop. Seeing that all the players are still young, they can still develop rapidly and become top players. Arsenal's problem is just a storm of injuries and the consistency of this game is what Arsenal are afraid of. Last season, Arsenal's performance from the start of the season was also very convincing, even Man City was far behind Arsenal in terms of points, but in the last few matches at the end of the season, Arsenal's spirit seemed to be broken and it was true that at that time several of Arsenal's main players were injured.
This season there is no reason to repeat the same mistakes as last season, Arsenal's players this season can be said to be almost complete, from the core players to the reserve players. Moreover, they have beaten Man City, maybe this will be a big motivation for Arsenal to win the EPL this season.
Last season happens to be the awake call for Gunners, they were very competitive and led their preeminent opponents till the very last games, when they started declining in performance due to absence of the key players, inconsistent performance became the orders of the day for Gunners. However they're all in the past, forward to the present. Arsenal are on fire this season with spectacular performance in league games. Mikel Arteta and his men have learnt their mistakes, they look forward to correct then this season. This is a new different EPL campaign, numerous teams are in the race for the EPL trophy but it's crystal clear the teams that would earn important spots and the ones that would be relegated this season.
Well, Arsenal indeed had a spectacular performance last season until they started disappointing as you said, I personally believe that the EPL trophy was theirs to carry home last season, but unfortunately, they lost their first position in the EPL table to Manchester city after either losing or drawing some crucial games which lead to them losing some really important points.
Here we are in this season now and the same Arsenal is on fire again just as they were last season until they began to mess up, i really hope they did learnt their lessons through their experience last season just as you have said.
But one thing I personally think is that, this season's EPL looks like it's more competitive than the last one, teams like Tottenham and Manchester city are all gunning for the EPL title, Arsenal will have to play harder and smarter than ever if they must have the chance of going home with the trophy.