So... What will the next DLC be about? I'm going to make a prediction now so I can have bragging rights if it turns out to be true.
The next DLC, I think, will expand on some of the quests from vanilla Skyrim, mainly the war quest line. After having won Skyrim, we set out to defeat the Thalmor. To do this, we must venture out of Skyrim and into Cyrodiil.
While there, we could also join the Fighters Guild or Mages Guild. Or we could continue the Thieves Guild or Dark Brotherhood quest lines by joining up with their branches in Cyrodiil.
Spell creation and/or spell combinations will also be introduced.
As for the minor DLC... I have no idea. Horse armor? More follower commands? Spears? Playable Werebears/Wereboars?