Mistakes must have been learnt but not completely. Arsenal is still yet to sign a perfect replacement for Saka just incase Saka gets Injured for a long time.
Neto the Portuguese winger has been linked to gunners, I do hope he gets signed up.
Mikel Arteta had a good squad last season, he wasn't having enough depth and replacements for important players.
Against Manchester City, they played well and Mikel Arteta did his part well also. He brought in the perfect players to win him the game and also to hold down the game for him.
Arsenal should have learnt from their mistake last season and i believe they won't like to take chances, they would had won the league if not for the injury crisis they had last season that cause them to drop points, therefore they've got good substitutions for some of their attackers for instance Trossard is a fine sub for Martinelli but as Saka got injured the team still did good against Man City without him, however they'll still need to get suitable substitute player for him cause they might not be always lucky playing with him or a good substitute for him.
I think more additions should be included by the winter windows they'll need to strengthen all part of their squad against injury sp as not to share same fate as last season's, well i enjoyed their game against city it was very interesting, they gave there best amd it was very good enough to secure them the three points.