As it stands now, the only ways to get 4 channels of audio on a recording are:

1) Use buses MA/FG

2) Record more than just 4 channels of audio

3) Use the multicorder or second recorder to record an entirely separate video

Obviously, if all you want is just 4 channels of audio, the last 2 options are a bit ridiculous, given the amount of unnecessary overhead.

And there are plenty of options where you don't want to use M as per common practice or MA doesn't otherwise fit into your workflow for an ancillary recording.

For example, I like to record guests on separate tracks.

When I have just myself and 1 guest, I use Bus D.

When I expand to guests 2 and 3, I'd like to be able to use DE.

I cannot do so with vMix as it currently is, unless I also record every bus (all 16 channels) or record another video file, despite having no additional video to record under my current workflow.

It'd be much simpler if I could just set DE as a 4 channel recording option.

+1

+1 and for steaming.
And to expose the audio selection in the API/shortcuts.