The short Carnival cruise are notoriously party cruises. The Dream is not. The Dream and Fantasy are essentially the same ship. I've been on all the
dcl ships and the second newest carnival ship. If I was going to write a review I would write one that compared the ship, service, food, and public spaces. I wouldn't even compare atmosphere. The atmosphere changes from cruise to cruise even on Disney. It can be a different atmosphere based on embarkation Port, the number of kids on board, the cost of the cruise etc. Lots of variables there.
If someone cruised for a week on the Fantasy and 2 weeks on the Wonder. They couldn't write a review because one cruise was longer then the other ? That seems silly.