1. When I hear Hearthfire, being the TES geek I am, the first thing that comes to mind is the Redoran Hearth.
Culturally, members of House Redoran (who traditionally have always warred with the Nords, since their ancient city of Blacklight is right across the mountain border from Skyrim) always had a hearth burning within their homes. There is a lot of symbolism here, it fits with the rugged/homey feel of Skyrim, and it rekindles a lot of old aggressions between the Dark Elves and the Nords, which is referenced A LOT throughout the main game.
2. The book series 2920, The Last Year of the First Era that gets referenced in relation to Hearthfire (although that may be a stretch, seeing as Hearthfire is just a month within that year) is very focused on the Dunmer. The whole story is focused around the interaction between their god Vivec and the Empire, specifically the Akaviri Potentate. The Akaviri already have a lot of connection to the Dragons, and the Dunmer are already in a very good situation for an interesting story, with all that's happened to them.
A three way conflict between the Nords, the Dunmer, and the Akaviri is interesting and grand enough for a DLC storyline of epic proportions, but not large enough to be told in an entirely new game. Plus, the Nords have fought the Akaviri, too. Conflict of interests abound, and lots of "the enemy of my enemy is my friend." There is also the potential for a large land area surrounding Blacklight, which can easily be separated from the rest of Morrowind, due to the destruction that's happened there (and the mountains). If Bethesda wants to tell a great story that adds LOTS of new content, lore, and style to the game, while still maintaining the feel of Skyrim and immersing the DLC with the base game, this is the storyline that needs to be told.
Comments? Opinions? What do you all think?



