There is a possibility that Madueke will be placed on the left side/Left Winger because Arsenal only have 2 players for that position so Arteta needs new players to anticipate injury problems, while for the Right Winger position Arsenal already has 4 players. From the performance side, Madueke looks fine and he is included in Artena plans to build a young squad and yeah 23 years old Madueke is worth as a future investment.
Two left wingers isn't a small number for a team like Arsenal, although both could be used in every match, with Madueke playing half the game and the other half. However, I see Arsenal's move to acquire Madueke as a remarkable one, as they understand the weaknesses in their current squad. As for the right winger you mentioned, it would be quite sufficient if Arsenal had four players for that position, as three would be more than enough, including to address any injury issues that arise during the season.