Well, we need to prepare for the next gen dragons, i.e. the winged ones. Perhaps even if Glaurung isn't needed to father offspring for the Nirnaeth; that could have happened off-screen, then the reveal there's more of them would be more shocking. But then we might need to be able to justify significantly more dragons having been engineered possibly before Glaurung gets Gurthanged, and pulling the same trick again won't work. And being part of the R&D for new types of dragons is a bit more of a time investment that begetting a bunch more (however that happens!)
A winged dragon lady (or several of those) having a flirty witty discussion with a surprised Glaurung would be quite cinematic if done right imho. The action itself needs not to be shown.
Again with Glaurung and the plague that hit Hithlum, given that we know that Glaurung can 'foul' the pools of Ivrin, I wonder if he could be a source of water-borne disease (cf the famous
Broad Street cholera outbreak, which people at the time thought was caused by a "miasma"), but it could be put in a way that's not so clinical, and couched in Tolkienian terms.
Imho convincing.
As far as Dior goes, the choice to me seems: give up a quiet life in Ossiriand far from the Front to a) live with the Men and try to claim some kind of lordship ("last of a ragged line, etc"), and maybe try to have some impact, or b) go and be king of the Sindar in Doriath. The latter has a much better chance of achieving something meaningful, even if ultimately it really doesn't. And we are leaving out succession planning and also suggestions of Melian, here. It could be that Thingol appoints Dior his heir by fiat, in the admittedly unlikely case that he dies in battle, or if not heir outright, as a kind of back-up king (not a great suggestion, sounds bad when I say it). Or Melian could, just before she leaves, strongly suggest that Dior come, when Thingol dies, as a last act to look after Doriath and maintain some continuity in leadership for the sake of the people.
[
We will have later Tuor becoming the lord of human refugees after having fled Gondolin also just on the basis on his descent, also after several decades of absence and with no problems - and nobody of those humans
ever saw him before or heard of him as he was born after his father's death and among the elves and his only contact with humans before was as a slave to the Easterlings for three years as a teen.
What is the
real difference between a
"
Hi, I am Tuor son of Huor, my mother was pregnant when she left, you do remember? Who will follow me?"
and a
"
Hi, I am Dior son of Beren, yes, that Beren son of Barahir you heard of cutting the stone from Morgoth's own crown. He cannot come - due to circumstances - but he taught me everything he knows. Who will follow me?" ?
A mortal is
very unpractical as an elven king. He and his successors will
die too soon to implement any sensible elvish policy, leaving his people heart-broken again and again - having also to witness the dispair and fading of their mourning elvish widow queens.
Dior being choosen as Thingol's successor
cannot be Melian's idea, she must be aware of Dior
dooming himself with it, he dies before his 40s as a result after just 3 years of reign - not in 80-100s that could be assumed, or even more, if the Duneadain rate is to be applied to him.
No way she would advice such a fate to him and his sons. (If read this way it was Thingol unwilligness to "let" Dior "leave" - to go where he belonged (among humans) or even just stay neutral and letting him stay at his waterfall in the Blue Montains that doomed Dior and his family).
Dior becoming Thingol's heir makes only sense if
1) Thingol's plans to
sail after Luthien's second death - knowing now how bad he took the first one
2) He wants to cut of Dior and his sons form their human line and in his hybris to claim them for himself - in naming them after himself - "Elu" seeking to
override their mortality by his own claim - and as an unintended result dooming them to die much faster than they otherwise would - as he was effectively if unwittingly trying to circumvent the rules of mortality approved by Eru himself as the fate of fallen mortals - and such a challenge to the rules cannot go "unpunished".
Note that
neither Tuor nor Earendil -
despite being Turgon's officially declared heirs and while actually ruling over elves (and men) - never claimed kingship over the elves - maybe understanding that such a challenge to their mortal human fate would actually shorten their lives as it seemed to have shortened Dior's and his sons. As an irony both of them a reported to have been counted among elves after that for other reasons - maybe partially also as a response to their self-restainment here. Elwing - the only one of Dior's children not named after Elu (- but just after the startlight on the spray of the above mentioned waterfall - maybe after Melian having advised Nimloth
not to let her be named after Elu)- seemingly not claimed by him -
survived also and she (Elwing) chose an elvish fate out of love for her elvish mother Nimloth - now eternally widowed when reembodied. But they did it "by the rules" - not claiming it but being granted it.
In a way Turgon - while not above reproach himself - is a foil to Thingol - both their kingdoms do fall - but far as dealing with a human son-in-laws is concerned Turgon clearly wins the competition.
Thingol's kin Ororpher or even Celeborn were much better suited candidates to succeed Thingol for the interest of Doriath as a kingdom than Dior was and turned out to be.
