You would think that, but look at Oblivion, with the Shivering Isles.
TES IV was not named after a province
and recreating all of morrowind or cyrodiil would require much more effort than the shivering isles. it would be a whole new game.
Why not? They can do whatever they want. It's already confirmed that dlc will be big, what's stoping them from making all of tamriel? They already have the basic terrain done, all they need to do is flesh it out. After that it's just lore, quests, and hidden goodies.
they have very very rough terrain done. there are years and years of work to be done to make all of tamriel.
i hearby propose a wager. i say future dlc will not be a whole, complete province or all of tamriel. $200 down. anyone take me?