I don't know if NCL has a staff that actually read these review but if they do, I have some suggestions that may or may not be supported by other passengers. Everyone's experience is different on a ship and everyone has different tastes and interests so read reviews objectively.
Embarkation and disembarkation. 15 minutes to first embark and 10 minutes to disembark and find luggage. The best I've experienced in 9 cruises.
Deck 5 was close to everything; guest services, dining, Atrium, shopping, and the theatre.
Our inside forward cabin in the 5100-5200 location was perfectly situated. Small but efficient use of space. A light in the closet would help greatly but there was plenty of room for two to store their things. Closet is a little small so travel with things that don't need hanging. Our cabin steward Wayan was excellent. Attentive but not lurking. Granted all 2 of our requests and was always cheerful despite a very difficult job. Unless there is a free upgrade, we always go inside cabin. We were concerned about the size when we saw it listed on the ship outline but it was more than enough space. Our hotel room in Copenhagen was the same size. Ha!