Pros: Everyone wants to expand on the Great War and Aldmeri Dominion story. Revisit parts of Cyrodiil. Fixes the branch of the Civil War questline so that no matter which you chose, in the DLC both will wish to take stop the Thalmor and begin a new line of emperors. It's been a tradition that each of the empires begin with a Dragonborn (Alessian, Reman, and Septim). Possible mechanics during the war like creating a squadron with multiple followers and using some better follower mechanics in the Game Jam video like favorites and training followers.
Cons: Inablilty to give a correct name to the new empire because of the player not having a set name. Some people may say it is to early to go back to Cyrodiil