I Have Spoken said:
I want to believe in this, but I fear it is going to be a huge flop.
It's a pretty interesting setting, but the I don't think the challenge is the lack of material to directly adapt.
The Second Age exists primarily as a broad historical outline, with a couple of brief essays, plus plenty of incomplete (and often contrasting) narratives.
So, on the one hand Amazon has a ton of freedom to work with. The lack of narratives and plot gives them plenty of freedom (what do Gil-Galad and Elrond talk about, how does Sauron entice men and dwarves who just fought against him to accept Rings of Power, etc). They can invent plots, subplots, major, minor, and recurring characters and well as their personalities and motives.
The drawback, in my opinion, primarily come from audience expectations.
The two most well known bits of Tolkiens world are LOTR and The Hobbit. Those are narratives constructed around quests: destroying the Ring, and reclaiming ancestral treasure. Everything else that happens is in support or addition to the core narrative of the "quest"
Nothing in the Second Age is built around an adventure. Instead, what we know of it primarily is told through the perspectives of powerful dynasts and ruling figures. What drives the Second Age are their rivalries, alliances, and personal disputes: Noldor against Silvan Elves, Noldor and their friendship with Dwarves, Sindarin and Silvan elves dislike of dwarves, Noldor elves under Celebrimbor against the Noldor led by Galadriel/Gil-Galad (echoes of the house of Feanor against Finfolfin), Numenorians friendship and eventual cultural jealousy and hatred of elves, shifting Numenorian attitudes towards the normal men of middle-earth, Kings Men against the Faithful, and a charismatic, machiavellian, and most importantly, present Sauron playing these conflicts against each other to his own advantage.
In short, this should be more similar in many respects to GOT than LOTR, even if it does not revel in cynical political power struggles and lacks the gratuitous nudity and violence of the former. A Tolkienesque tale would show those to be a fruitless waste of energy and effort rather than glorify then. You can see the evidence of this in the subplot regarding Aragorn's claim to the throne, as told in LOTR + the appendices (IE, book version), or how the mistrust of the various kingdoms of the elves constantly undermined them in their wars against Morgoth (sure, the war was ultimately unwinnable, but they got in their own way too many times to even have a shot).
Lastly, there is the scale of the conflict: Sauron was a civilization ending threat for nearly two millennia. His rise and defeat in the third age is a blink of an eye by comparison. I hope Amazon communicates the scale of this conflict, and allows us to see how mortal men and immortal elves would actual perceive each other and why beings with such different perspectives would actually want to keep each other at arms length.
I don't know how receptive the general audience would be to this sort of story.
