I always wondered how the dawnguard intended to protect all of skyrim as well as keep a constant flow of information, or how the volkihar were going to increase their influence in skyrim once the little family feud was over.

How good would it be if after clearing out caves of vampires for either side you then had the option of occupying it with your faction?

It would make sense of how the dawnguard stay aware of current events and how the volkihar was keeping a supply of thralls.

A good example would be redwater den...

for the vampires

and for the dawnguard