Thanks for your insights and pointing to actual mechanisms that to you are vital to achieve a more natural timbre.
(addressed by you to the OP)
You mentioned full scale symphony. The ability to convey the hall ambience on a good recording again goes back to getting the reflection field correct, as the in-room reflections are in effect the "carriers" for the reverberation tails on the recording. I can go into more detail about this if you’d like.
I'm certainly all ears for an elaboration here.