I guess many current processors/AVRs and multi-channel sources
have dedicated 'stereo' LR outputs (in addition to the HT-type LCRetc multi-
channel outputs), making a unity-gain pass-through less of a necessity,
especially if they are not variable level outputs.
But are the pre-pros/AVR's set up that way? It would bug the crap out of
me to need to mark (and remember to set) the two-channel-pre gain knob for a
'calibrated' HT position, mentally deal with an unnecessary gain/loss stage,
and repeatedly need to explain operating procedure.