I like this. I'd also say that key changes are analogous to both highlighting strengths (doing a higher version of a kick, because you damned well can) and dealing with weaknesses (doing a slightly lower kick, because you are less stable on the high kick). And pace changes are analogous to...pace changes, as well as to intensity changes.There are some great songs out there. Take the "Star Spangled Banner." It has been rendered many times over the past century. Whitney Houstin, Jimi Hendrix (instrumental only), and various pop, soul and operatic singers. Each has put their individual touch and artistic interpretation on it.
Yet, the words have not changed - The meaning has not changed - Only the pronunciation, inflection and pitch. This allows each singer to explore the sounds, have it fit within their physical vocal range, and make the song "their's," without changing the message the song was designed to convey and pass on.