The Essence of the Tale

[Kuruharan]

I don't believe there is much that can be altered in LotR that could be removed without altering the fundamental character of the story. Some minor things like Tom Bombadil and Ghan-buri-Ghan can go without too much damage, however, LotR is a finely crafted and balanced thing designed to be what it is (tautological as that sounds). It will not sustain major meddling and retain its essence, and in fairness nothing really will. This is why adaptations are difficult.

One thread I see already in this is that, although duty and sacrifice are necessary, tweaking things to emphasize that more would often remove the reward that should come of it, which changes the message rather emphatically.

As you say, you can further emphasize the element of sacrifice, but you quickly get to the point where you diminish the eucatastrophe. In my view, all of the elements in LotR are similarly balanced.