You may be right comparted to other public metadata services (are there any?). But I can relate with the OP’s frustration, although I would not call Roon unusable for classical collectors.
I am using Roon exclusively with my local library of around 10K classical albums and by doing that I am already in 2 minority groups… 
And certainly not in a group where Roon’s development focus lies.
What frustrates me most, is the “lack of control” Roon allows me in terms of my metadata. My file tags are in very good shape and I’d be happy to live without all the work descriptions and album reviews and artist bios, if Roon would allow me to take full advantage of their database model for composers and compositions using my metadata.
There are settings to “prefer file” almost everywhere but yet they don’t seem to do what I would expect. Roon always wants to “outsmart” me. If I set my library settigs to “prefer file” for compositions I expect Roon to do exactly that. But yet there are so many cases that I reported in the past, where this preference is just ignored.
I personally don’t need Roon to improve my metadata in any way other than providing relations between my existing metadata like artists, composers, and works. This alone would make me happy and would be worth the price. But what I see is that if I follow this “prefer file” paradigm, Roon still interferes with its magic.
I do understand why so many people could not be happier with Roon, but for my personal use case, it has developed into quite a nuisance. Minim Server could be a viable alternative but then I would need to find a way around my existing endpoints which are based on raspberry pi setups. I did not investigate yet in that direction.