There is an article coming out soon in Positive Feedback Online where I was interviewed about amplifier technology. I explain the gap between specifications and sound quality. I'll be posting a link here when the article is available:
http://www.audiocircle.com/index.php?topic=127654.0
I believe I get where you're headed, especially with the link you provided and really, screw the specs, because I've seen some great specs with crappy sound quality. However, in relation to the aforementioned Chord amps, the premise is that what goes into the amp is identical to what comes out, so the specs, themselves, are there to merely say that the THD+N is well below what's audible, but the supposed magic is that if you have a DAC that is 1% THD+N you're going to get exactly that from the amp. And so on and so forth.
Of course this is all I theory, because it's still in the works and I have no idea if they'll be able to pull it off. Still, I know that's the goal.