Well I like this carnival view "bigger is not always better"
I can tell you there are few things I'll like to see on a ship taht does not involve big ships;
1. A roller coaster, have you ever been on a video roller coaster where the seats movement give you the idea you are really moving when you are not? I think this was on Florida Disney world or something like that...How about that in a ship for the kids?
2. You can put like "The big FAN" apparatus that pull you up, giving you the idea of flying and integrate some view from the top of the ship, i don't know but it can be a great family fun.
3. How about a astronomy observatory on the top of the ship?? like a planetary??
4. How about a PS3 on the plasma on the top of the carnival victory??
these ideas can improve cruising life without creating bigger ships...