Another thing to mention about these measurements is that it's difficult to say how much water is included in them. If someone considers water segments as exciting as land then it doesn't matter. If someone prefers more land, however, then he could be disappointed when he keeps hearing that TW3 is this or that times bigger than this or that game, and find out that sailing in Skellige or swimming in N+NML are major parts. Which so far seems to be the case (Skyrim doesn't have nearly as much water, and I don't know about DA:I). Add to that the difficulty to calculate under-ground parts in the games and the size comparison becomes even less helpful. So it's not as simple as saying the overview map is a certain number of square kms compared to the other game's.