While some strong teams in the Premier League like Manchester United and Arsenal are trying to hire more players and get their teams improved, I think we shouldn't forget about teams like Fulham since they also had good performance in the last season and now it seems Fulham hired Emile Smith Rowe the player of Arsenal.
Emile Smith Rowe is a young player and he is only a 24-year-old player. Emile Smith Rowe started his career in Arsenal and now he left the team at Fulham. He signed a 5-year contract with Fulham and I think Arsenal will feel regret because of losing a player like Smith Rowe.

I am more confident that if Emile Smith Rowe joins Fulham, Arsenal will not regret it.
He has experienced a decline in performance since the last few seasons while Arsenal is currently building the club to be stronger after getting 2nd position in the points table and has the desire to win the premier league title with productive players.
ESR is no longer very productive so Arsenal has the urge to sell him.
A player's performance can improve if he is with the right club while Fulham is not better than Arsenal who have better quality coaches and experience.
You can see here for details of Emile Smith Rowe's career during his time with Arsenal.
https://www.transfermarkt.co.uk/emile-smith-rowe/detaillierteleistungsdaten/spieler/392765Their is no reason for arsenal to keep him because his performance is not affecting the club positively, so I think Arsenal won't have any regret for letting him. It will be better if the coach can bring quality players because this is all Arsenal needs to defeat team like Manchester City. Arsenal really needs to strengthen the team for the new season because in this season Manchester may not even be the only challenge they will. The game Arsenal lose to Aston Villa is what made them not to be able to achieve the tittle of the league. They just need to try their best to have a very tough squad.