It's just that Arsenal also need to prepare more reliable players that they can use when a core player is injured or so they have more good options. because Arsenal will also fight in the Champions League in the coming season.
Arsenals coach Arteta definitely must have learnt a thing or two from the experience gotten last season and I think he would be more reliable to build a team that’s more consistent in their games for the next season.
I think the fact that when their top players were out of action due to injuries and the lot, they suffered some setback cause there wasn’t a reliable or capable replacement. He would need to work on that as well. After all, they’re now in the race for the champions league title next season.