I agree with this, the video operator is the one who can easily check
the levels being received and so should be aware of the nominal levels
This might be a deviation, but I think it might also be a good way of improving the audio quality and consistency significantly.
With regards to this specifically, I suggest that some sort of R128 monitoring be implemented in Voctomix. A really useful example of this is in ebumeter(1):
http://kokkinizita.linuxaudio.org/linuxaudio/ebumeter-doc/quickguide.html - it might be interesting to look at how it behaves when some previously recorded material is played through it, to get an idea of the readings it gives.
The I-value shows the deviation from target loudness - and the operator should ideally aim for a value of zero. This is quite a lot easier than trying to explain the concepts of loudness in relation to PPM or VU meters. If the value is positive, gradually reduce the signal level, if the value is negative, increase it.
The remaining risk beyond this is clipping - this can be reduced by using a limiter, or a soft-knee compressor before the signal is input into the computer.
For what it's worth, Nageru implements this form of loudness monitoring already.
David