Having the different versions of one work organized under a table of contents on one page to me seems neat and simple compared to accessing multiple separate pages.
That's the exact way it was ordered. A transcription would have its own page, and all other revision
and editions would be under it. It would not be on the original work page, but it would instead be referenced ("see also") from there. I don't know when you joined IMSLP KGill, but back in 2007 when the site was fresh, Liszt's section was pretty much like this: a transcription of a work was cataloged and ordered according to Searle's numbers, e.g. all different revision and editions of a Liszt transcription would be under the work page of Liszt and not on the work page of the original composer (only referenced therefrom).
However, if there would be two different versions
, e.g. one for piano solo and one for piano duet, they would have two different workpages, but only because they are ordered as such in Searle's catalogue.
Well that's the way it is for the majority of works in the library
Even if it's the way for the majority of works in the library, we have to be one step ahead and be flexible. Different catalogue orderings (e.g. that of Searle) require different approaches. Conventionality never goes to the books.