Nketiah scored 5 goals in 27 games last year. He wasn't a very productive forward. Crystal didn't start the league very well this year either. Arsenal actually lacks a forward like Haaland. The last time they didn't have a forward was probably during the Thierry Henry era. They must be an unlucky team because they've been feeling this lack for a long time. I think they need a forward like Haaland. Haaland scored 100 goals in 105 games for City. A statistic that could make them champions on its own.
Every player in the front line must have the instinct to score more goals because their job is to be able to finish well when there is a pass from their own team mates. While Arsenal's front line players are not like that although I also don't think they are bad because for this season Arsenal is still quite good in the domestic league and also in the Champions League. So they only need a few new adjustments to be able to increase their strength in the front line even though they don't have players like Haaland who always get more support from their teammates.
The sale of Nketiah to Crystal Palace is one way for Arsenal to get rid of less productive players, he is one of the attackers born from the Arsenal academy but unfortunately he is unable to compete with other attackers because of his inconsistent performance so far, the only regret of Arsenal fans at the moment is the absence of new striker recruitment made by Arteta in the transfer market last summer and it clearly gives has a bad impact on their front line, indeed so far Arsenal has an attacking line that is indeed quite productive by relying on their two wing lines but obviously without a central striker it will hinder Arsenal in the fight for the championship trophy, Arsenal will face a tough match in the Champions League and also the domestic league and if they continue to force Saka and Martinelli obviously it will leave both players vulnerable to injuries which will ultimately cost Arsenal later, after losing Thiery Henri and Van Persie, I dont know why so far Arsenal have had difficulty bringing in a central striker who does have a fairly high goalscoring instinct?