I have a wish for the next Sprout (or Stellar) integrated. I would really like a device the can be connected to the tv through hdmi with CEC support for volume control via the tv remote.
The reason is that I would like something that is as easy to use as a soundbar, but with PS Audio sound quality.
Something like this starts to get pretty hairy. We’ve never been in the video processing game, and we don’t really have much interest in it. Stereo is our love and our specialty. Supporting protocols like ARC requires another level of licensing and would likely require different DAC architecture that might not prioritize stereo sound quality. Not to shoot anything down, but I doubt Paul has much of an interest diving into the AV game.
You don’t need video support to do HDMI ARC for audio. I completely agree that you should stay out of video 
I think of something like the Naim Uniti Atom or NAD M10 without the display.
You’re right, but it would most likely require multi-channel processing which is the more important aspect.