Add a big numerical Volume Level Display to the DAC1 HDR.  This display could show attenuation in -Db, or on an increasing numerical scale from 0 to N, or be switchable between the two.   It could be mounted in the faceplate or sold as a separate add-on product.  Check out the big displays on the ARC preamps or the cool dot matrix display on the Resolution Audio Cantata.  On the DAC1 HDR it would be nice to see the volume setting from across the room, and to be able to repeat exact volume settings when needed.