I actually think this is a pretty cool and logical idea, though I don't see it being implemented anytime soon. For full effect for me it would have to have things like meter feedback and sends, hence why people like herr_prof said it's mostly for non-chip trackers. It could be cool for playing live with Solo/Mute, but would probably be annoying with the button layout and not being able to, you know, touch the faders. But still, it would be a nice overall setup for soundchecks!
Renoise has this exact thing: A master fader for all channels in a Mixer Screen. When that was introduced, people didn't all say "omg you have instrument volumes/volume commands/rtfm," they just...used it