I think it depends on who the players leave and it depends on how Spalletti manages his players because as we know the current situation for Spalletti he is one of the smartest coaches in Serie A.
Last season actually proved how shrewd he was in spending and reshuffling players, especially I think many people were initially unsure, including myself in Spalletti's decision to let go of their core players like Dries Mertens and Koulibaly at the start of last season but he believed so much themselves by replacing them with young players.
It is possible that this season will be like that. Kim is most likely to leave but for others it is still uncertain so we just have to see how the transfer goes this time for Napoli.
Indeed, Luciano Spalletti management skills and Napoli's transfer activity will play a major role in the success of the team in the upcoming season. Being one of the most intelligent coaches in Serie A Spalletti will be essential because of his ability to lead and motivate his players. His shrewdness in reorganising the team and making tactical choices like as letting go of important players like Dries Mertens and Koulibaly which at first created questions among supporters and commentators was on display the previous season. Nevertheless his faith in the young players paid off and Napoli enjoyed a productive season. With players like Kim set to leave this season may provide similar difficulties but the unpredictability of others futures keeps us alert. The results of the transfer window will ultimately influence how Napoli looks for the upcoming season.