Those are huge ships. The one I went on is only mid-sized, and it can carry almost 2000 passengers and over 800 crew. It has 5 floors of passenger cabins, and 9 stories total. Crew is all housed below the waterline. 2 sit down dining rooms (huge) where you are served at the table after ordering from a limited menu and there is also a large self serve dining area, buffet style (my favorite), in addition to a little like "fast food" place for burgers, hot dogs, fries (kid's favorite)... There are several bars and lounges, coffee bars, and restaurants, but these you have to pay extra. Big performance stage for shows that are every night, small movie theater, casino, little lecture hall, and meeting rooms, 2 swimming pools, hot tubs, a spa with services, and kids only areas. When you walk around you will discover nooks and crannies where there might be a small band playing with a little dance floor. My favorite place was called the crows nest, near the top, with 180° of windows, comfy chairs, a library, board games, and puzzles. There was also a bar and a coffee bar up there, so some people were happy!
As for feeling the water, when out on the open ocean in rough sea, we could feel it a little, but you got used to it very quickly. Our cabin was way up in front near the prow, so in rough seas, we could really feel it while sleeping, but it felt nice to me. Kind of like swinging in a hammock. Cabins toward the center of the ship have less movement, kind of like how a teeter totter doesn't move up and down much in the center. If you want to go fishing, you can do that when you get into port.
Ohh my the thought of feeling like you are swinging on a hammoc while trying to sleep is making me feel woozy... But I get motion sickness on a swing.