First for the non-Carnival specific stuff for those who've never cruised before ...
Most of the time, we never really had an issue with boat movement or sea sickness, but for one leg of the journey, there were storms all around us and it was pretty rough. You couldn't walk without having to hold onto something or bounce off the walls. One couple we talked to who were veterans even said it was really bad. My wife and our 10 year old both got very queasy during this part of the trip. Unfortunately it was rainy and/or old during both ports of call so that kind of put a damper on things. I found the ship to be somewhat crowded and a bit confining ... the pools were small, the lines seemed long and most activities were in use all the time (maybe this is specific to the ship).
Carnival Victory review ...
Positives - Great entertainment! Way better quality than the cheesy stuff you get at most resorts. The food was excellent and plentiful. The ship staff were helpful and in particular the wait staff in the dining area were fantastic. Great kids club for tweens (12-14).
Negatives - One shuffleboard court. No balls for the mini-golf. They basically showed football constantly on the outdoor big screen ... only one night of movies (and not good ones). Over-priced arcade with absolutely NOTHING free in the games room ... not a single kid in there using it. Our 10 year old was too old for the kids club (mostly just little children ... they need to make a 9 to 11 year old club if possible. Lastly there was no separation of the casino from the rest of the deck and the arcade was right around the corner from it, so you had to walk through everyone smoking when you got off the elevator or stairs ... they really should have the smoking areas isolated with a doorway.
If you've never cruised before, I think you need to do a short 4 or 5 night trip and experience it for yourself if you're curious. Not sure if we will go again, but if we do it will be on a bigger ship with more stuff to do and more amenities/passenger.