A good example of writing music beyond one's technical abilities would be Absurd's pre-Werwolfthron work. The melodies are beautiful, the only hindrance is the technical incompetence, one imagines them hardly able to finger the chords properly or keep in time (for a direct example, "Requiem" the one recorded in prison). The point is though that they were clearly working on some projection of the music that was inside their minds, and the result was that although they were hardly able to play it, the melodies are visible, simply in a sputtering signal hampered by inept instrumental training. To really listen to music, one has to disregard technical skill, disregard production, disregard everything except the music. Obviously, the non-critical elements can be beneficial to better expressing the music's ideal form, but it's not necessary. In fact, even disregard the instruments. To quote Joseph Haydn "If you want to know whether a melody is really beautiful, sing it without accompaniment". If a melody does not sound beautiful on the human voice, why would the instrument change anything? If the melody itself is the most important part, one's ability to play it is a good thing, but playing a boring melody well is worse than playing a beautiful melody poorly.