There are many issues with the Composition view and indeed Roon’s handling of classical music in general , that said Classical metadata is a mess of note. Who in their right mind would use the Artist Tag to store the Composer ? Deutsche Gramophon for one it would seem. (a historic effect of the original Tag Definition aimed at pop music and not specifying a tag for Composer)
Roon does a reasonable job where there is no complexity eg your average Symphony , Concerto etc . As ever Roon is only as good as the metadata it can find, so where its wrong its wrong at source
Two examples come to mind
Large Pieces ands Excerpts
As @Jez points out in a Mass or indeed in an Opera it is common to find a single movement or a single Aria where Roon identifies it as “the Work” eg The Overture from an opera shows as “The Opera” so you can see many instances of that work in your local library or in Tidal/Qobuz that turn out to be a single track . Here there is no indication of which is a Full Work ands which an Excerpt so unless you know which is which you are lost.
Works in sets or single movements
A good example here is Chopin’ 24 Preludes Op.28 (indeed a lot of Chopin’s works) . It is common for artists to record an album of the complete set of 24, equally it is common for a Recital to contain only selected individual Preludes. This is where consistency goes out .
If an album contains the complete set , normally Roon shows this as Preludes(24) for Piano Op.28, if an album contains only one it shows just that one as below
One could argue that each prelude is work in its own right ie Prelude Op.28 No.15 in which case all 24 should be separated out but this is clearly not the case here
Its a matter of consistency the result here is a mess …
No amount of adjustment externally of the Work & Part tags fixes this , you simply learn to work around it , not ideal. Other more customizable solutions allow a finer control but at the expense of a large manual intervention.
I have come to the normal love hate relationship, I put up with the bits I hate for the overall benefits of the bits I love. Its why I run 2 libraries . For even modest box sets Roon is quite unusable unless you have an encyclopedic knowledge of what music is on what disc.
Classical music is a minority genre but ignoring it doesn’t make it go away. The answer to poor handling of big box sets is not to buy them is a bit rude to classical fans to say the least, alas.