I see impossible to see Napoli being champion of the SerieA back to back, they never do something like that plus Inter needs to win something asap after losing it all in the end of the last season.
This plus this Napoli seems to be the best one and when this kind of teams are in that particular position they start to fall.
Never say never when it comes to football. If Napoli were able to win the league trophy last season tell me why it is impossible to win it this coming season with the recruitments they have made to further improve their team. I think it is very possible, their team looks very organized and stronger for next season.