[davem]

Littleman Poet, I think we're coming together - I thought for a while there that we had a different understanding of this subject.
I don't mind subjects going off at tangents, as long as they're interesting.
I can't help but wonder whether readers of the books have missed a central issue. I do get the impression that a lot of readers think Tolkien was holding up the Elves as admirable ('Look at this ideal race of PERFECT beings I've created, aren't they wonderful). For me that's not it. He is exploring ideas, & themes such as power vs powerlessness, time & eternity, & ultimately, Death, seen from the perspective of & in contrast to an everliving race. After all, how admirable are the Elves? I'm old enough to remember when the Silmarillion was published. The reaction of many readers to the portrayal of the Elves was very condemnatory. They liked the Elves of LotR, beautiful, tragic, etherial, but Elves as proud, violent, intolerant, even cruel, wasn't what they wanted at all! I don't think Tolkien saw any of his races as 'ideal'. They were all flawed, but as we see from his later writings, the themes he was exploring grew more & more to dominate, & the central theme is the inevitability of Death, & how we deal with that one inescapable reality.
As for the Half-Elven, this is a very complex matter - how can they choose? To the extent that they're Elves, how can the understand mortality? To the extent that they're mortal, how can they understand immortality? Assuming that its not just a choice between dying or not dying, & that its a change in their essential nature, how can they make an informed decision?
Also, you come to the question of to what extent death is part of our nature - if its a 'gift' is an 'extra' an 'add on'. Or does it 'define' us, is it part of our 'essential being'? Is it the greatest gift we could have been given? Our transitoriness is central to our achievements - art, music, science. The knowledge that we will one day leave this world, but the sense that that is not the end, is the central fact of our nature. ~I think Tolkien was interested in themes like this, & that that's what he was exploring in his writings. That's why the Legendarium isn't a 'fantasy' story, just another tale of Elves & Dwarves, Wizards & conquering heroes with magic swords, fighting & defeating the usual 'Demon King' who wants to take ove the world & enslave the 'Free Peoples', etc, etc.
Its a dark tale, set in a dark world (our own) where the end, for us & for all things, is inevitable, & all that we have to hold onto is 'Hope, without guarantees'.
(By the way, the 'mallorns in Aman' thing isn't original, it was from Paul Kocher's Master of Middle Earth).