If hardware changes are on the table, I'd much rather see one that can turn infinitely in both directions and only report the change rather than an absolute value.There is still the hardware option to use it as a real analog attenuation device for the separate DAC + amplifier (like Pandora).
But we have not yet tested that any of the prototypes. It needs hardware changes and someone to write appropriate sound driver code. So we simply do not know if and how good it can work.
Using absolute values has one minor benefit (surviving an unexpected reboot without committing every change to flash), whereas relative values enable a lot more functionality (dual purpose for brightness, application-specific vs global volume, etc) and avoids other more common problems (not being able to have alarms loud despite whatever the desired application-volume is).