I must admit the idea of the size and being sea worthy is mind bending and an achievement scientifically speaking. On a personal level it make me ill to think ant one would want to ride on it with that many other people. To crowded for this person but so are any other cruse ships. I fear for any animal that swims below them it must be deafening. I know it is bad enough in the St. Lawrence when a cargo ship goes over head when I am diving. I can be very disturbing the first few times then just annoying.
The bigger they are the less they may see to your needs. It also may be more of a security risk. I do not like them too huge because of this. Engineering wise it is an achievement but so was the Titanic.