A toggle switch in the album details settings page that groups by Work only when any of the tracks on the album has the tag “is_classical” or one of the genres is Classical.
Problem solved
Solves the issue of albums with Work tags splitting every track into its own group on the album details page.
Brought benefits
While the Work tag is primarily useful for Classical albums, I find it helpful to also tag all tracks with their Work as it allows me to group covers and remixes and similar re-recordings of the same base track together.
My two cents: it seems like there’s someone asking why they have “duplicate titles” at least once a month. If this feature were added (and set ON by default) it would probably help cut down on that.
This is exactly how MusicBrainz Picard uses the Work tag, which is why the “issue” I mentioned pops up so often.
There are a lot of people who know nothing about tagging their own files, who just run their library through Picard and say “Oh goodie, now it’s all fixed for me!” Without knowing the details of how or “what has been done”–like the Work tags that Picard will have added.
IMO your request helps the “Group by Work” feature to only show when it is most likely to be useful (Classical genre), while keeping the current behavior available for more advanced users who actually want to see this field.