Actually, one could spend a month on the Oasis and never see the ocean. It really is a floating city, to the extent that you rarely realize you are on a ship. One should view the video on the Oasis construction to really appreciate the design and assembly of these monsters.
We had one of the "Inside Balcony" cabins, overlooking "Central Park". Don't bother. Since there is nothing to look out on except a few trees and a few folks strolling along the sidewalks, it becomes boring after about 3 minutes. And, the view never changes! The cabin appointments were OK but the cabin itself was a little small, compared to other ships we have sailed on.
The Shows are, for the most part, terrific, almost Broadway quality. However, the methodology for getting in to the shows, making reservations, standing in line for everything, not knowing were to line up for standby makes the entire process terrible. RCCL needs more signage and a better method for show access. While, in the end, everything seemed to work out OK, all the show entrance processes are a mess.
The Wi-Fi arrangement is not as good as some of the other ships we have been on, either the network capacity is commonly exceeded or the RCCL setup arrangement does not work as well on such a large ship.
Watching an outdoor movie in the sun is a waste of time, even if the movie is a first run hit.
The food was fine, not exceptional, the buffet area upstairs is way too crowded and laid out very odd. The doughnut shop served the worst doughnuts I have ever eaten. A complete wast of time.
The Roast Beef Sandwiches in the Park Grille were outstanding.
The water shows were wonderful, the Aqua Theater is amazing. Again, difficult to believe you are on a moving ship.
All in all, we much prefer a smaller ship, with more traditional arrangements.
With regard to the ports, a common T-Shirt says "Same Crap, Different Island" and I paraphrase the saying. That about says it all.