Rowan,

Horn and reed players are trained to play notes from the page, and can live happy and productive lives without ever doing anything else. Unless you play jazz or such things, there is generally little need to create your own part.

What Tom Loy and Ian Blake could do(and I would have absolutely loved to hear it) was a product of their own imagination and creativity, applied lovingly to a kind of music they knew and understood--you can't expect the same from every other horn or reed player--