These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Obvious Beta: And Tropes Are Not Bad, but it was plain Tolkien intended to do more work on it, both in adding to descriptions and in filling in certain (sometimes fairly long) gaps between scenes. May also qualify as What Could Have Been, as one of the "longest tales of the Elder Days" could likely have been even longer if it had been brought to its final completion.
The version of the story in the Silmarillion of 1977 is less detailed and more chronicle-like, but because of that it feels more complete than this more novelistic treatment.
This version is largely based on the version in Unfinished Tales, a more Obvious Beta.
Glaurung, with his dying breath, chides Túrin for the many atrocities he committed; he notes, however, that the greatest atrocity is the one that is sleeping in his sister's womb.
What no one seems to focus on - and admittedly the incest is rather distracting - is that Túrin essentially marries a child. Yes, Niënor was fully grown, but the Niniel personality is only a few years old at best.
The description of Glaurung's belly is thoroughly revolting.
Pretty much the whole thing, but Beleg's death, and Niënor's and then Túrin's suicides probably beat all else out.
When Húrin and Morwen are speaking of what will happen in the coming days of war and then:
"That night Túrin half-woke, and it seemed to him that his father and mother stood beside
his bed, and looked down on him in the light of the candles that they held; but he could
not see their faces."
Lalaith's death from sickness.
The epilogue — Húrin, released from Angband by Morgoth to live out his last miserable days, makes his way to his children's grave. He doesn't need to read the memorial standing stone — he knows what it says, but huddled beside it is his wife, starving, haunted, and bitter. It's the first time they've seen each other in twenty-eight years. She starts to tell him what happened but he already knows. She chides him for being gone so long, he can only reply he returned as soon as he could. They spend a few moments together embracing before she dies in his arms. You've got to be made of pretty stern stuff not find that the most aptly tragic end to a story.
What Measure Is a Non-Badass?: When Gwindor returns to Nargothrond with Túrin, he has learned a some things about Morgoth during his thralldom in Angband, and has the wisdom to see that Nargothrond must remain hidden and wait in hope for the Valar to deliver Beleriand. Unfortunately for poor Gwindor, he's now bent over, crippled, traumatized, and decidedly non-Badass, so everybody ignores his words. Even when Ulmo's messengers tell Orodreth point-blank that Gwindor's right, the king still takes Túrin's advice and goes to open war.
Everybody, but Túrin, Niënor, and Húrin himself qualify most.
Mîm the Petty-Dwarf as well. His hatred and betrayal were completely justified after Andróg killed his son.
Poor Gwindor had to watch his brother being horribly dismembered, then he was enslaved and repeatedly tortured in Angband for 17 years. When he finally escapes he's maimed and traumatized, and when he manages to walk all the way home his fiance falls in love with Túrin, his whole country decides he's too non-badass to respect him any more, and then the kingdom is destroyed.