Many people hate dragons so it could never be the spotlight of a game...beth knows this
Which is why I said that I'm sure it won't be
solely about vampires, and that there will be other stuff to do for those among us who do not like vampires.
The files also mention a snow elf prince and children crying, but that doesn't mean that the Falmer are going to be the spotlight of the dlc either.
Skyrim's main quest is the best example for what I was saying: the main quest is about dragons, but the main quest is quite short and you have tons of other things to do. There are ruins to explore, different guilds to join, people to help/kill and none of these things have anything at all to do with dragons. Some people even ignore the main quest of Skyrim entirely and still have fun playing the game for 200+ hours.