As a "commoner", ouch! (though it is true)
But I know what he means about the creative process. It would be the same in any medium, be it a novel, movie, etc. Whether you're making something entirely original or, in this case, using a source for inspiration and/or substance, the joy of creativity is a big part of the reward. If OCR rejects your tune, well, that's their prerogative. You can tweak or overhaul it to meet their standards but, if that results in a remix that you no longer enjoy, what's the point? If it gets posted, great. If some people like it, wonderful. Others may not. Different strokes, folks. Creativity is personal expression and as long as you're happy with the final product, even if it doesn't make it big, congratulations on a job well done!