@mkgus
Good luck putting those concepts in a formula.
Your post nicely nailed that. Now if I could add something. The reason that the formulas are lacking and the ear/brain has a marked advantage is the ability of the ear/brain to hear into noise floors/ceiling which as I mentioned earlier is a serious limitation for measurement systems. And this is especially important in the room generated lower frequencies ( room "lift" is a big issue below 500hz and it generally gets quite dramatic at around 125hz ) where we can be pretty successful hearing thru the reverberation artifacts and microphones not so much ( actually their issue is they pick up everything and can't separate the wheat from the chaff the way our ear brain has evolved to do...and while we can do that trick it is much more enjoyable not to have to, which is where successful room acoustics comes into play ).
And speaking of the experience issue mentioned above "my day job" is in the film industry were "we" provide/build good acoustic environments in which microphones can more efficiently capture sync sound off the floor. "We" have been doing this for over 35 years and have contributed to over 65 major film and television projects. We have successfully worked in tiny rooms and in rooms as large as 15 million cu ft, This is why I sometimes "lose my mind" and blather on about microphones and acoustics because this is what I have done, and if the repeat business is any indication, quite successfully, read, I would like to think I can speak from experience and a reasonable understanding of the underlying theory.