Music for an instrument co-evolves with the instrument itself. If an isomorphic piano pushes music co-evolved with a conventional layout out of reach, it would

Music for an instrument co-evolves with the instrument itself. If an isomorphic piano pushes music co-evolved with a conventional layout out of reach, it would equally bring music that hasn't been written because it works poorly with a conventional layout but works with the isomorphic layout into reach. And yet some other layout would push some things out of reach but bring other things into reach. Which is to say, it isn't a surprise that music co-evolved with a particular instrument might be difficult on some other one; it's the expected, perfectly normal, perfectly predictable result, and isn't really a criticism of the new instrument. Unless you're willing to equally criticize the conventional instrument for all the music it can't play very well, but then, even so, it's a very symmetric criticism in the end and doesn't amount to much.