I think your approach is very well written and very to the point you are seeking to make. If there is an answer to this issue it can be found in the same manner as would be used to determine whether chocolate ice cream is better or worse that vanilla ice cream.
For the most part I think you are dealing with issues to which there is no or very little objective proof that one opinion is correct and one is not. In other words we all have opinions on things the correctness or truthfulness of which is not easily provable if provable at all. On the other hand, what fun would a horse race be if everyone knew who the winner was before the race and there was no judgment and betting involved before the race. There is always going to be differences of opinion and that is what drives people in selecting certain products over others, different cars over others, different speakers over others. \
I think there are a least two variables here- one is the person's judgment that a system is too harsh or too laid back, etc. and the second is that person's judgment that changing a cable or the position of speaker or effecting some vibration control etc. corrected the problem -based on that person's first judgment- that there was a problem that needed to be corrected. If it could all be objectively measured I think if wouldn't be nearly as interesting.
