Just look at the Steps of Faith. We all know it is longer and wider than what we see from Central Coerthas or from Stone Vigil. Part of the problem also with making areas match their actual size is then needing to fill it in with places. Too few and it feels empty. If you do the opposite then you have the pressure to make it feel lived in. You don't want 1.0 Shroud where it was mostly empty while looking samey. You also don't want FF XV where there are things to go to but not much to see once you go there so it ends up feeling empty.