The Grand Princess and her sister the Golden advertise the largest casinos at sea. The casinos on the RCI Eagle class vessels (Voyager, Explorer, and Adventure of the Seas) aren't exactly tiny either :-).
I was on the Explorer of the Seas in March 2002 and I thought the casino table area
was small. There was not room to walk behind the tables and had to wait for a
seat to be open. They had other tables but rarely opened them. They had a couple
of pretty good nickel slot machines. There was more room to move aroun the slot
area than table area.