Well that sure did highlight a lot of Napoli's problems. I think it's fairly obvious their defense lacks personnel to compete properly at this level, in a lot of the set pieces they were dominated. Losing Maggio would have been a big loss in that respect, as well as going forward. They also cannot chase results against stronger opposition, you just have to look at how out of their depth they appeared at the end, there wasn't a game plan. Good run for this year though, probably best for them that they can focus on getting back into it for next year.
This competition is going to be decided in whichever round Real Madrid and Barcelona play each other in by the way.