User blog comment:Jimeee/Bethesda tweets mysterious teaser picture.../@comment-5500417-20121103032943/@comment-108.180.205.201-20121103223550

They have all the Thalmor stuff to set the tone for the game. As is stated numerous times in-game, the Empire is crippled from the war, and the Aldmeri Dominion runs things. Doing that allows them to create tension in the world. Also, it provides an offset for joining the Imperial Legion which, in other games, they lacked. You join the Legion, but there wasn't any opposing faction. Now, with them having the background of the Dominion, the Stormcloaks rise up, thus giving players more choices in the game to suite how they want to play.

Addressing the Thalmor issue means they would need to address the entire issue of the Great War, as they tie into each other. Solving a war is just to grand in scope to be solved with the addittion of DLC, unless is was a freaking huge DLC.