The increase in size definitely serves Carnival -- increases profit margins -- but does not improve the shipboard experience for passengers. It seems that Carnival increased the passenger count disproportionately to the size of the ship's spaces and the crew:passenger ratio.
The Conquest/Triumph-class ships are maintained beautifully. I didn't see much difference between those and the new Magic.
1) Lines are long everywhere (customer service, shore excursions, food stations, et al). Just get accustomed to waiting -- even more than normal.
2) Getting a table at the Lido buffet is a challenging, even going well off-peak. You see a lot of people with filled trays wandering around, looking frustrated. Since the ship is overpopulated, there are limited places to play games and cards elsewhere, so people camp out there, taking up tables for people who would like to enjoy their meals while they are hot!
3) The elevators are inadequate for the number of passengers. Count on a very long wait. Sadly, the elevator situation brought out the 'strongest survive' instinct in many passengers, and many handicapped people were stuck. Be prepared to be aggressive - or climb stairs. We were on the 11th deck; a lower deck would have been more convenient.
4) Entertainment venues fill up well in advance. Plan on arriving 45 minutes in advance for smaller venues, like lounges, and 30 minutes in advance for the main auditorium - or you'll sit behind a pole or stand up.
5) It goes without saying that embarkation and debarkation are even longer than usual. Self assist is a must!
6) I read an analysis of the Costa Concordia disaster that it is impractical (improbable) to evacuate mega-ships like this one. They aren't meant to be evaluated at sea, but rather designed to limp into port. That raises a number of security concerns that I hope to find reassuring answers for (e.g. what about onboard fire?).
**Food was seriously disappointing.**
1) The Lido deck buffet served exactly the same English-style breakfast day, after day, after day. If you like peppery bratwurst, grilled tomatoes, and poached or scrambled (powdered) eggs, you're all set. If you long for a sausage patty, or bacon.... Sorry. Lines for the omelet station grew longer and longer each day. If you can, go to the table service at one of the main restaurants.
2) Whoever did the desserts on the buffet should be shot! Seriously. The chef screwed up even easy recipes. I tasted a cake that was supposed to be peach, with a peach glaze, and it was absolutely vile! I rarely met a dessert I don't like, but only good manners kept me from spitting this one out. Blech.
Northern/Southern Lights dining room
1) There were a few 'standard' Carnival recipes, and those were still good, but the rest were 50/50 hit or miss.
2) The dishes served in the dining room shrank portion size considerably. Actually, that's a good idea since you may or may not like what you order. I recommend getting two appetizers to cover your bases.
1) The cheese on the pizza (available 24-hours) is pure rubber. Absolutely no flavor, and it doesn't break down when you chew. My DS suggests getting the Supreme so you don't notice it as much.
2) The room service menu is understandably limited. What was surprising was the Lilliputian size of the sandwiches. They were so cuuute! (Order two.)
In summary, I just don't see the advantage of cruising on a new, larger ship.
I was impressed with the magic show (awesome!), and the passneger talent show were really good, as were some of the comedians. This is where Carnival spent their money. (I wonder why a helicopter was a necessary prop when it only appeared for 30 seconds, and not used for any magic tricks.)