What I would like to see is a DLC where you're sent to investigate some type of anomaly by a Jarl or whoever else. And you're actually captured and taken to an ancient SURVIVING Dwemer city that has been cut off from the world for hundreds of year. Possibly being over run by Falmer? Just an idea.
Kind of like the Lost City of Atlantis idea or the City of Eldorado like Disney used.(examples off the top of my head)