Do the agencies themselves realize the subtle benefits of UI/UX changes to websites, TLS, etc? I don't know exactly what all 18F does but it seems like those are among the features I see changing (and appreciate).
Line offices are at the pointy end of the stick where you actually deal with citizens. In my particular case we do a lot of permit issuance and resource management, but yeah think local branch office where you go when you want something.