Maybe its just me, but I think map sizes are kinda a silly way to measure the size of a game world. As contradicting as that may sound.
To me, I think if a game world is well designed the size would just feel right. There is this almost magical way a game world can make you get lost in it and not because its just vast and you forget where you are but because its well designed. Where you can kinda use landmarks to chart your way through it without having to refr to a world map every 100 steps.
Kinda like how it was n SotC and games like ocarina of time and soul reaver.
But what do I know.....