Tolkein is a complicated guy to discuss. There are certain core elements of his works that would be really sad to lose, and others that would be really sad to keep. GoT set in Middle Earth is just about the worst thing they could do, that much I agree with. There is no (or rather, very little, and none on a large scale) moral ambiguity in LotR - there is a right thing to do, and a wrong thing to do, and everyone has a pretty god damn good idea which side they are on as a result; the only "ambiguity" is that sometimes magic is powerful enough to sway people to the wrong side as they become corrupt, but it's still clear that they're becoming corrupt/evil.

The worst thing about Tolkein is how deeply ingrained (and critical to his themes in many ways) his concepts of racial essentialism are... a hobbit has these traits, at its core, and is fundamentally Good; an orc has these, and is fundamentally Evil. There can never be a "good orc." There can never really be a "bad elf," or a "bad hobbit," not unless they are twisted away from their essential nature by a much greater evil. The men of the "east" and "south" (aka Asia and Africa, because it's extremely apparent that Middle Earth is a layout of Earth and the Shire is his home in the UK) are dark-skinned, and aligned with Mordor, and evil. Anything "black" and "dark" is evil, anything "white" and "light" is good, the fairer-skinned and more pure-blooded you are, the better; when your pure white blood becomes intermingled with that of "lesser men" you lose things and become weak and begin to fail. Anyway I have rambled on too long, there's plenty you can look up on this subject if you really care - but stuff like this makes it hard to just view Tolkein's philosophy clearly, and it's a hard subject to work around while maintaining the essence of a capital-letter Good vs Evil conflict. Not impossible, but ... well, I don't have much faith. It'll probably just be GoT in ME anyway.