It is true that Napoli has changed their poor performance, and they were lucky enough to win the Scudetto this season, but I don't see Napoli as the favorite to win the Scudetto next season because if not for Inter Milan's busy schedule in the UEFA Champions League competition, Napoli wouldn't have won the Scudetto this season. In my opinion, Inter Milan is the favorite to win next season's Scudetto because they will want to make up for their mess next season.
The fact for now is only this Napoli gets rid of their bad performance and they win the scudetto title. It may be their luck and their hard work which leads them to the success. As the perception for the next season someone is said over here Inter Milan is the most favourite. I think there is no doubt that Napoli has changed a lot in the context of performance and they make a possible win but for the next season they are also undecided whether they win or not. Besides Napoli it is undecided for almost every club who will be the next winner in the next season. So, let's things happen and then decide who will be the best among all. Because there is a chance that the best one may lose their main strength and those not considering much strong may enhance their performance as a result of a great success.