So, La cathédrale engloutie is a piano piece, and it was written for the piano, and sounds very good on the piano. I have no objections to musicians and composers transcribing well-known piano pieces for other instruments, or for orchestras, but sometimes only the original instrument conveys the composer's intentions satisfactorily. (Occasionally it works the other way: Ravel's orchestration of Moussorgsky's Pictures at an Exhibition is probably superior in almost every way to the original piano version. The piano version is marvellous, and exhilarating to play, but a full orchestra has the capacity to give depth and breadth and variety to the music in a way few pianists can.)
However, just this week I've heard two other instruments playing La cathédrale engloutie, one a guitar, and the other - just this morning - a harp. Nope, this piece doesn't work on either of those instruments: the sonority of the piano is totally missing, the ability to sustain notes with the pedal while others are being played is totally missing, the wondrous booming bass pedal note that thunders through the piece again and again cannot be achieved on either a guitar or a harp. I could barely hear this bass note in the harp version - there was a kind of clonk somewhere in the depths every so often - and while the guitar achieved the effect a little better, I would guess it was at the expense of shifting the registers of the original music around.
I suppose it must be disappointing if you're a harpist or a guitarist not to be able to play all music written for the piano. It sounds like an easy process of transcription really - all three instruments have a fair number of notes at their disposal; all three can play chords comfortably. But sometimes you harpist or you guitarist just have to admit there are certain pieces that will sound worse if tackled on your instrument. Please refrain from playing those.
I wrote some piano pieces early last year - after I'd finished writing the music for Grimhilda!. Not one of these four pieces would sound effective on a guitar or a harp. They rely on the particular percussiveness of the piano, the ability to wash the notes together with the sustaining pedal, and the wide tonal range that the piano has. I'm going to keep them hidden from any guitarists or harpists I meet...