We were just debating the objectivity of the concept of accuracy. And it seems it was just shown it is not totally objective, as we can not reach a quantifiable state. As you know room acoustics, particularly small/medium room acoustics is very subjective - although there are some general accepted rules, each provider of acoustical treatments has his personal solution.
Yes, it does seem to get a bit messy when you release the sound into a room. Before that, even, as even great transducers don't seem to be capable of the fidelity of decent electronics. But even that can be measured at the listening position. Electronics, of course, are much easier, but the fundamentals remain the same: The component, transducer, room treatment, system that most closely reproduces the recorded signal in the listening position is the one that is the most accurate, the most transparent.
The most "natural" relative to some non-existant event? Now that is completely subjective - without any generally accepted rules.
Tim