Perhaps better known for his solo piano arrangements of Bach's music (e.g. the Chaconne for unaccompanied violin and the Chorale Preludes for organ) than for his own compositions, Ferruccio Busoni also published his own editions of much of Bach's keyboard music, though his revisions are so extensive in some of them that they can hardly be called "editions" by modern standards. In the preface to his edition of the Goldberg Variations, he writes:
"In order to rescue this remarkable work for the concert hall (that is, to give the thousands, who cannot reproduce it themselves, an opportunity of hearing it), it is necessary — more in this, than in the others of Bach's Pianoforte compositions — either by shortening it, or paraphrasing it, to render it more suitable both for the receptive powers of the hearer, and for the possibilities of the performer."
Accordingly, he suggests omitting nine variations (a suggestion I chose to ignore) and reworks many of the others to match the piano-playing styles of the nineteenth century (though it is a testament to how far ahead of his time Bach was that Busoni had to do so little to achieve that goal — for example, the opening of Variation 28 sounds like it could have been written by Brahms just by transposing it up an octave, and Variation 25 already sounds like a Chopin nocturne as-is). Similarly, he deleted 12 measures from the first movement of the D-minor concerto, and 40 measures (not all consecutive) from the third, which I decided to restore and "busonify" to match the style of the rest of the piece.
I think that Busoni's attempts at modernizing Bach deserve more attention than it now receives, not only because they are an important part of the history of these pieces, but also because they are a possible answer to the question that fascinates me most: What if Bach had lived to see the piano evolve into what it is today?