Not gonna happen, plain and simple.
There is a small chance that they'll include the western part of Morrowind, since it is a small sliver of land and it wasn't in TES III, plus it would allow for more land to border on the ocean, which is a great natural barrier to the map. Other than that, if you want more land, you should just hope that Bethesda increases the scale of the land from what it was in Oblivion. This is actually very possible, as the earlier TES games were MUCH more massive than Morrowind and Oblivion (albeit with terrain that was generated by an algorithm rather than by hand).