Not sure why you specify "past" here!
However, bench testing is very important, IMHO.
The actual power is generally a non-issue. I don't crank it hard and find my 50WPC Marantz NR1605 does fine on its own with most speakers I have had, and I have the extra external amps to use for any speakers which have abnormally high demands. So whether an AVR delivers 120 or 160 WPC X 2 or if it is at .1 or .002 THD is not directly critical to my decision.
However, I do see measured power/distortion as a reflection of how much effort the manufacturer decided to put into overall design/build quality of that model! I make these associations without the statistics to back it up, but when you have limited data available, educated guesses become relevant.
More importantly, I look at these test results as a pulse check on the companies. For example, Gene has measured several Marantz AVR's and mentions their 70% rule which states they will produce 70% of their two channel power rating when driving 5 channels at once (IIRC). Marantz seems pretty consistent in effectively meeting this standard. I find that makes buying a Marantz AVR a safe choice. Similarly, Denon always seems to produce strong measurements (though I don't know that they have a self-imposed standard such as Marantz has with the 70% rule).
If we ignore their past HDMI failures, which I believe to be corrected in new models (God help Onkyo if they are not), Onkyo has the benefit of THX rating which is an assurance that the amp won't crap-out as soon as you ask it to pass significant current. Seeing this confirmed in the measurements is reassuring.
The relevance of these last two paragraphs is I'd feel comfortable buying a Marantz, Denon, or Onkyo
which has not been measured because of the pattern established of meeting or beating their claimed ratings and decent 5 channel performance. If I was buying the budget models from any of these companies, then I would want model specific data, but for mid or higher models, I feel like they have established their capability.
In the case of Yamaha, I would really want specific data from the exact model I was considering. The mess with the A860 undermines my confidence in them. At $900, I consider it a mid-level unit and Yamaha has named it as among their prestigious
"Aventage" product line. This leaves me with a lot of concerns about how well any of their other products will perform! I know Yamaha is fully capable of having excellent amp sections in their AVRs and believe they still do in their better models, but knowing they are willing to cut corners in ways that won't show up in the specifications, but could in actual use results in uncertainty on which models they would do this on... as well as whether power is the only metric they have chosen to "economize".
So, for me, there is some utility in specific model measurements, but more in using the data to reveal overall trends of the approachs the different manufacturers choose for design their products!
