Mikel Arteta has done a fantastic job this season. This is really commendable, if they can maintain the consistency at the end of the season, maybe Arsenal would be the champions of this season. But it was their misfortune that they could not win the championship. As Arsenal will play in the Champions League next season. So they need a stronger squad. The Champions League and Premier League are very competitive. It is much more difficult to maintain consistency in both places. And so in addition to strengthening Arsenal's squad, they must also keep their bench team strong. Otherwise, Arsenal's performance will suffer badly if a key player gets injured.
Agree with you, Arteta has been fantastic this season, apart from them not getting any titles this season but Arsenal's development under Arteta has been quite impressive. When Arteta started training Arsenal, many sneered and insulted him. Not a few people even told Arteta to leave Arsenal. Many said they lacked experience, didn't suit Arsenal's style of play, etc.
But now a lot of people adore and praise Arteta, you see, everything needs a process, the arsenal is inhabited by young players who have high egos, mentality that has not yet been honed in accepting the pressure of the opposing team, but look now Arteta is able to control the ego of his own players , succeeded in building a much better team mentality, as a result the combination and teamwork became better.
even though at the end of the season you have to settle for second place, Arsenal still have a long way to go, look at the progress from season to season. This proves that a quality coach is not seen from the way he came and immediately made the team a champion, but seen from every progress in playing from season to season. Yes, it's true, as you said, Arsenal in the transfer market must actively bring in top players to strengthen their reserve squad because next season the challenges will be even tougher.