Let's just address the elephant in the room head-on. This is the fourth (possibly fifth, if you count Monster Mythology) time I've read more or less this exact same book. And, honestly, I don't know how I should be feeling right now. There's a reason I wanted to read these books, but I've forgotten what it was. Deities and Demigods (Rich Redman, Skip Williams, and James Wyatt) has made me forget.
It is, in many ways, a deeply flawed book, but the flaw is the same flaw it shares with this entire tradition of D&D supplements, going back to the original 1st edition Legends and Lore (and presumably to the version of Deities and Demigods that preceded it) - it's a monster manual that shouldn't be, and doesn't want to be, a monster manual.
So I could just say the same thing about this version that I said about Monster Mythology - it would be a much better book if they just tore out all the stats and made each entry twice as long. But I can't say that, because this book differs from previous outing is that if you tore out all the stats, each entry would be 3-5 times as long.
And if you do that math, you might think you see the fundamental problem - obviously, they shortened the deity descriptions to make more room for stats. That would be a serious flaw, and the exact opposite of what they needed to do. But that's not what's wrong. I went back and checked. If you excise the mechanics, the flavor part of each individual entry is roughly as long as it has been in the past. Maybe a bit shorter than Monster Mythology or On Hallowed Ground, but longer than both versions of Legends and Lore.
The difference is that the stat blocks are now up to two pages long!
And that brings me back to my opening question. Why did I want to read this book in the first place? What was I hoping to gain? Why was it even published?
I'm not sure the authors of this book could answer the question any better than I can.
My feeling here is that it can be broadly considered a "toolkit" book. It's filled with elements and options that allow you to insert gods into the game, whether as distant, mysterious figures, active adversaries, or even potentially peers to the PCs. Yet it kind of feels like the sort of toolkit that might be designed by someone who's only encounter with an actual tool is the allen wrench you get when you buy flat-pack furniture.
This book doesn't seem to understand religion, or faith, or mysticism, which is maybe a lot to expect from an rpg book (and certainly something I feel awkward, as an atheist, calling someone out about), but it also gives us game mechanics that would allow a literal man to fight a literal god, somehow without ever incorporating any of the elements of a classic "man vs god" story.
(Oh, fuck, have I just found myself yearning for a "Theme" and "Mood" section? Maybe I owe White Wolf an apology.)
The disconnect here is that when you put the gods into a story, even just as distant patrons or an overarching campaign villain, you've entered the realm of mythic storytelling, where heroes engage with, at least, the ruling values of their culture and, at most, the primordial mysteries of human existence, and even if the only story you're telling is about how a bunch of rogues punched them in the face, by necessity, those rogues are punching them in the face mythically.
But though it occasionally relays stories from classical myth, Deities and Demigods never really engages with the concept of myth, either as a worldbuilding element or a genre element. In the divine ascension section at the end, one of the suggested adventures is about someone who meets all the known prerequisites for ascension but fails to become a god. And so they hire the PCs to investigate why the ascension failed.
Could you imagine reading that story in a religious text? Or hearing it around the campfire? It's barely even a fantasy story. Oh, let's investigate the gods, so we can see what they're hiding about the process of transcending your mortal form and gaining the limitless power of the divine. I mean, why not, right? If you can fight them, then surely you can take them to task for misrepresenting the true nature of apotheosis. Just a different sort of conflict, is all.
Which is actually where I think the root of this all lies. D&D is only good at depicting certain types of conflict, and therefor only good at telling certain kinds of stories, and in almost all of those stories, the gods are at best a mascot. Something for the cleric to shout out as they're clubbing an animated skeleton with their mace.
You can keep a little bit of the mystique of such beings by making them pure plot devices, but the second you make them actual characters in the world, they just become another sort of monster. And while it's certainly possible to depict monsters in a way that makes them feel spooky and mysterious, D&D 3rd edition kind of prided itself on being able to put a setting's mysteries into a predefined box (oh, please, do not get me started on how similar most of the gods' statistics are - Hephaestus can Use Rope with a +41 bonus, Tyche and Athena are limited to +37).
Those comfy little boxes are probably how we wound up with the Divine Salient Abilities section. I actually had to write down in my notes a reminder not to harp on how weirdly underwhelming almost every single one turned out to be. So, just one example, the power of Create Greater Object.
To gain this ability (which, I must emphasize is the greater version of this godly power), you must have a Divine Rank of 11 (an Intermediate Deity - for reference Demeter is rank 10 and Dionysus is rank 12) and an Intelligence score of 29. It allows you to create any object you can imagine! Up to 100 pounds per Divine Rank. And if you create something that costs more than 100gp, you have to rest afterwards - 10 minutes per 100gp of value past the first 100gp.
And look, that's not unimpressive. You never have to worry about encumbrance or petty-ante gp accounting ever again. And I suppose, if you had 16 hours of downtime, you could use that to add a single 10,000gp diamond to your True Resurrection stockpile. But let me pitch you an alternative. How about, with a single full-round action, you can create any object that will fit in your hands, regardless of value, and you can do it as often as you like. And if there's any significant downtime at all, you can create palaces, fortresses, megalithic statues of yourself, or anything else you can think of.
The natural objection here is that such an ability would be incredibly overpowered. A character who could do that would break the setting over their knee. Every single encounter or challenge would have to factor in their ability to simply create whatever item they need to address it. You would have to put them in ludicrously contrived situations that will seem more like jokes or folk tales than rpg adventures . . .
Ah, of course. The fact is, Deities and Demigods uses a 3rd edition rules chassis, and the implicit gameplay assumptions that come along with it, so there was never going to be any way that it could handle the scope of its own premise.
Which brings us back to my original quandary. Why does this book exist? Who is it for? What did Wizards of the Coast hope to achieve by publishing it? My theory is that it was made to cross an item off a checklist. It was a supplement people expected to see, and so it was made to satisfy those expectations. It's not completely bereft of insight or merit (certainly it has the advantage of being less offensive than 2e's Legends and Lore, albeit at the expense of being less diverse), but it also doesn't quite manage to sell a vision of bold new gameplay possibilities. I'm actually kind of relieved it's the last version of this supplement WotC ever made.
Ukss Contribution: My opinion of the book wound up sounding pretty dire, but aside from the stat blocks, it was mostly okay (Loki fucks the horse, which isn't a selling point, per se, but does at least indicate an intention to deal with the subject matter honestly). My favorite part was when they were discussing methods of divine ascension and one of the suggestions was that the gods would hold a tournament and grant apotheosis to the winner. And, look, I know that's not what the plot of Mortal Kombat was actually about, but it's what I've always imagined it to be about, and now I want to do it in D&D.