I personally think that maybe Napoli can do better this time. They haven't been regularly joining the Champions League above all else. Therefore there was some lack of experience. They still did great last season of course. Because they made it to the quarter finals. However they couldn't deal with Milan obstacle despite a big effort.
But this time I will be expecting an even more competitive and aware team. They should be able to develop better strategies against especially the experienced teams of the tournament. When it comes to their group now I can just say it is quite easy for them. We should be watching a tough fight between Napoli and Real Madrid for advancing as the leader.
Real Madrid might be their biggest challenge, I'm not ruling out Union Berlin and Braga, it's just that Real Madrid seems to be the only one.
Experience in big competitions like this is very important, here the club is not only required to play well, but mentality and experience are two things that are tied together. If we go back to last season, I can say that they were game ready, but mentally they were still lacking so they lost to clubs from the same league because they were more mental and also more experienced.
They need to show that they can not only play and have a good mentality in Serie A but also here.