A double blind test was already done. The results are well summarized in this article
http://www.hometheaterfocus.com/receivers/amplifier-sound-quality.aspx
The test was done by an expert in double blind testing. 60% is failing so don't think they could actually tell the difference remember that means for every 10 comparsions they guessed 6 correctly. That's very low odds. And likely would have converged to 50% as the number of tests went to infinity.
IOTW you're wrong according to the study done.
The conclusion Sound isn't what you consider when buying a AVR or Pre-pro amp. Reliability, Cost, True Power, Looks, Features, Connections, Brand preferences. Don't waste your time with other junk. Focus on what matters.
I know it all seems mysterious, but it isn't Power supplies are very similar and all perform the same function and send that signal to the same speakers.
Now of course with a pre-pro setup you can use EQ's and active crossovers to improve sound quality. So that should be remembered. Though many receivers now use AS XT which for most people does a nice job.