However, expansive as it was, it was still a small-scale model of a realistic terrain. We know that in the TES universe Skyrim is smaller than Cyrodil, but I would be happy to find that TES V uses a larger meter stick than TES IV.
Not having played TES games before Oblivion (nor Fallout since) I'm not aware of the precedent on this issue, and of course there must be balance between world size, density, travel time, and the technical limitations of the engine and hardware.
I don't expect Skyrim to contain the full-scale realistic terrains of, say, the background mountains in Crysis (Some imported directly from Hawaii), but I think a scale 2X-4X larger than Oblivion's would be managable and desirable. With a reported 7000-step climb up the Throat of the World, I'm hoping Bethesda can deliver.