I guess the difference here is actual square mileage and content.
See, it is true that with the larger estimates, the area of Cyrodiil is 16 square miles. The smallest state in USA is Rhode Island at ~1500 sq miles.
However, if Cyrodiil is about 4 miles on side then I should be able to walk (average human walking speed is 4mph ) from, say, Chorrol to Cheydinhal using direct paths in a bit over one game hour.
But this is not true. To compensate for time and space issues, he developers tied Speed attribute to actual speed and then balanced against time passing.
The effect means that if you walk, not run, from those two citites, it will feel as id you are going an epic journey between places. On top of that, many roads climb and bend, and many players would take side trips to caves/ruins or fields to pick flowers.
This content manages to mask the basic fact the Cyrodiil is tiny.
Using Acadian's figures, we can establish the ratio of city distance vs. width of Cyrodiil for Oblivion (average of 50 miles between cities, making Cyrodill 225 miles wide.) However, his figure is skewed as he lowered the base timespeed from 30 to 10, throwing his calculations off. The figure I come up, by dividing Acadian's highest figure with my own and then multiplying the result by 225, makes Cyrodill about 684 miles at it's widest point.
Yep, that prety much represents what I mean with some better numbers.
For me personally, the world is plenty big because of this effect.