Hope is everything to Men. It is in hope for a life of something better did the men run to the west, in hope of the land where Shadow may not reach us. That hope seems to fail, but it is not the only Hope Men carried with them. And if takes a thousand lifetimes of Men for this Hope to come true, what does it matter? What matters is the surety and a complete belief that our Hope is true, and that whatever will be lost to the war, whatever strength does the Enemy gather and whatever lands does the Shadow cover, all will recede like the darkness before the sun, all dark strength will be for naught, all that was lost will return in full, and all that was marred will be restored. It is with this Hope supporting them shall our people live and fight and die, and do so knowing that all their efforts were not in vain, and that any victory the Enemy gets is only temporary.You've packaged a lot into the premise of defiance which is not present in the text itself. What is Hope to men who have never seen the Light of the Trees, never seen aid of the Valar in years of running, whose entire history has shown that the world doesn't belong to them? How many lifetimes of Men will it take for stronger powers to intervene? Men have seen no power greater than the Shadow, but why should that rule us, for even as late as a few turns ago, we wiped out an entire band of the Enemy's servants with no casualties. Even under a fatalistic world view, even if we accept death by Morgoth as inevitable, why should that make us give up and die? It is already the Gift of Man to die, so let us live in a way we can be proud of. Let us grow mightier and mightier and add to our chronicles, spiting the Dark Lord who sought to snuffle out the Children of the Sun in our youth. And again, in regards to being Feanorian, they no longer ruled their lives and instead bound themselves up singularly in their possessiveness and spite. We've sworn no Oath, we are yet free. Your points however are well-argued, and a worthy alternative.
What does Defiance offer us, in place of that? An acceptance that our hopes are empty, that the Enemy's victory is inevitable, but also a promise that in his victory, we shall make him pay dearly for dashing our hopes. Oh, that would not make us give up and die, far from it. Should our people accept that promise, I do believe they could draw a lot of great strength from it, fighting on and on despite the odds. And yet, I don't think that this strength would be greater than the one we could draw from true Hope, for that strength would be based on our acceptance that we cannot win, that all the parts of the world in Shadow will stay there, that Enemy's strength is greater than those of all others and will eventually overcome us, that those words convey our situation the best:
Lay of Leithian said:and Morgoth was a king more strong
than all the world has since in song
recorded: dark athwart the land
reached out the shadow of his hand,
at each recoil returned again;
two more were sent for one foe slain.
New hope was cowed, all rebels killed;
quenched were the fires, the songs were stilled,
tree felled, heath burned, and through the waste
marched the black host of Orcs in haste.
In my opinion, accepting such disheartening things as truth would be a burden on all our people, and that every time they would gather the strength within them to raise in defiance despite that truth, it would take a great toll on their spirit. Because it is incredibly hard to fight on and on, time after time, if you also believe that with every your victory you merely delay the inevitable, and that there is nothing to hope for but that prolonging, and yet that there's also no other way but to fight. So I think that all strength that promise would give to our people would also drain them terribly, especially when the going gets really tough. The option says about turning our people against the shadow in their heart, but I'm afraid we will not be able to truly overcome it, for this shadow within is the same as the Shadow without, and we start with accepting that the Shadow without is the master of the world - how can we really expect to overcome it, then?
The Old Hope, in difference to that, establishes that there are powers beyond the Shadow, even if we are not, and thus we only need to believe in them to raise our hearts beyond the Shadow too. It has its own difficulties, because the greater the Enemy will seem, the harder it would be to believe that there are truly powers beyond him, but I believe that overcoming that would be easier. A belief that not all is lost is alluring to accept, often a healthier outlook then just defiance and, last but not the least, it is also the truth. Men might not now this for sure, but Eru is indeed beyond Morgoth, and I believe that the world will have its ways to convey the truth of it to those who believe.