Bethesda officially announced their latest DLC for the game that keeps on giving today. The "Dragonborn" DLC seems to add a whole unforseen load of new features including but not limited to:
Morrowind
Dragon Riding
New teir of weapons (correct me if I'm wrong)
New storyline
Please remember these are only things revealed in the trailer and there may be much more in the final DLC. No more onformation has been released.