I asked Michael Ibsen about the difference between music written for guitar by guitarists and and non-guitarists.
The guitar has so many little idiosyncrasies and restrictions, as well as special ways to achieve a certain effect, that I find playing music written by non-guitarists often feels like a process of translation. Even in cases like the music of Joaquin Rodrigo, who wrote extensively for guitar, you sometimes find passages that are either straight-up unplayable, or written to try to achieve a certain effect, but not done so deftly. Usually in these cases it can easily be solved by re-voicing some chords or moving a melody to a different voice etc, so it’s still possible to achieve the effect the composer wanted, while making it idiomatic or possible on the guitar. The published editions of scores that Andres Segovia edited are famously full of huge changes, to the point where when I pick up a score of a piece dedicated to Segovia and possibly edited by him I will skip straight to the manuscript if I can. The other problem is that every guitarist’s hands and musical tastes are different, so while his solutions to problems in the original piece might work for him, I want to see the manuscript to see if I can find a better way to achieve the effect the composer is after.