Well, I finished this about a month ago and I'm just now getting to the review. I don't really have an excuse, with current events I can't say I've been too busy haha.
tl;dr: It's quite good in many ways, but I do think you're a little hard on Christopher.
So this book is impressively thorough and I learned a lot. Some things omitted from the published Sil I already knew about (eg, Nerdanel), others I did not (the longform Oath of Fëanor). It's a nice roadmap to HoME, which has some real gems in it but sifting through the drier or redundant material can be daunting.
You are pretty critical of a lot of Christopher's decisions. Some of the points you make I agree with and some I don't. A few quick comments on particular issues, nowhere near comprehensive:
- The aforementioned full Oath and a lot of other things involving Fëanor in Aman should definitely have stayed in. The full Oath puts the doom of Mandos in a new light because he's more or less daring the wrath of the Valar.
- The published version of Ungoliant's death sounds a lot better. Also Wanderings of Húrin absolutely should have been an appendix in the CoH novel.
- Saying he should have reworked the 1917 Fall of Gondolin is asking for a bit much.
- Your point about the female characters has a degree of validity, but the "maybe Christopher doesn't like strong women" comment is over the line. It was probably unconscious.
- The Athrabeth...I dunno. It's a beautiful text and Andreth needs to be part of the conversation about Tolkien's female characters, but IIRC Tolkien himself had reservations about the idea of an incarnate Eru as "a parody of Christianity" and it's a big change to the mythology. Whether to make it an appendix or possibly try editing a couple parts out would be a tough decision. It should have at least been in Unfinished Tales, which is not widely known but still much less obscure than HoME.
- The loss of small details in various places is unfortunate.
However, a little perspective is needed - Christopher had a daunting task, very complex and completely unique. Critiques we make of his decisions are with decades of 20/20 hindsight, and
anyone in his situation would have made some mistakes. Furthermore, it's only because of the 1977 Silmarillion's success and his own dedication for years that we got HoME and can know about all the changes (and mistakes) he made. While you praise Christopher in some places, sometimes the tone does come across like a lawyer making an adversarial case and not really considering these factors.
Still, despite those misgivings I really enjoyed reading it (and I mean that, not just saying it to be nice). It's a great companion to HoME and would recommend it to people looking to go deeper after Unfinished Tales.