Why compare D:OS2 to Oblivion?
That's just a game I plucked out of the air as I recall someone saying that Cyrodiil's total area [...]
I'd hoped my point was that it's pretty representative of what we see. TW3's 136km² is, what, 2-3 times the size, not the orders of magnitude I was describing. They're all much of a muchness.