Great discussion .... another reason why being on the Chordie forum is so worthwhile.
I find myself of two minds on the subject. On one hand, I can't think of another art form where this level of license would be appreciated or even allowed by the original creator of the art. And I find myself appreciating such tribute bands as Brit Floyd and the Australian Pink Floyd Show, because they are meticulous to produce their renditions with note-for-note and tone-for-tone precision. A part of me feels that the original artist is really the only one with the right to make such alterations. And in classical music, a performance is often assessed by the integrity of the performance to the original music, apart from perhaps the mood or speed at which is was played (the conductor's influence).
But then (as musicians) we are in a creative genre that is not static, like a painting, a photograph, a sculpture, a novel, etc. And for that reason the element of ongoing creativity almost makes duplication possible or even desirable. I suppose before doing a different rendition of a song publicly, one might ask themselves if the originator would be complimented or insulted, and make a respectful decision based on that.