Then I read a book like Tome of Magic (Matthew Sernet, Ari Marmell, David Noonan, and Robert J Schwalb) and it really makes me wonder. This book introduces three new varieties of magic, each with a dedicated caster class, along with appropriate prestige classes, magic items, monsters, and professional organizations. And each one brings a unique and fascinating fantasy flavor. And two out of the three are functional enough to use alongside the core classes. But the book never even entertains its most obvious use case - creating new fantasy worlds where its new magic systems are just how magic works in that world.
I mean, I don't think I'm completely out of line for bringing this up. There's a general procedure for creating fantasy that I'm following here - you think about what you want your magic to do, both on a literal and a thematic level, and then you sort of shape the rules of how magic works to fit with those goals. Then maybe you extrapolate new things that may happen while still following those established rules and either tweak the rules to not allow things you don't like or just follow the chain of logic to create new things you didn't expect when you first set out. Because the role of magic, in fantasy, is to be a well of strangeness that takes us away from our mundane world (though the best fantasy does so in a way that has something real to say) while at the same time being coherent enough that we can feel like this new world might be a genuinely real place.
And judging by that standard, Tome of Magic might well be the second or third best magic book D&D has ever had . . . except it still keeps the core game's terrible "arcane" and "divine" magic as canon. Which means that you're not playing in a world where rare adepts of shadow can reach through the emptiness inside of themselves to draw forth the twisted prodigies of creation's dark reflection. You're playing in a world where people who do that are seen as a strange and limited variety of Wizard.
Unlike Magic of the Incarnum, which had the exact same fatal flaw, it's easy to adapt the new Tome of Magic systems to their actual proper use, but the book inexplicably does not help you to do that. It's like the idea was not even on WotC's radar. All of the classes and organizations get an "Adaptation" section and it's all folderol like "what if the class's alignment requirement were different" or "You can substitute in any generic death god if you're not using Orcus in the game." They're not entirely useless. Some of the advice sections might well suggest some fruitful tweaks. But they're all operating from a base assumption that whatever you do, you're still going to be in D&D-land.
It is an absolutely absurd proposition (bordering on the impossible) that when this book was being written, no one even entertained the notion of making a world where Truenamers fulfilled the same niche as wizards. There's a whole sidebar that begins, "The magic of names has been a theme in fantasy literature for as long as the genre has existed." And from there, it's only a short trip to the question, "hey, what exactly is going on with a spell's verbal components." It's not going to take a diagram to draw a line from the Fireball spell to the in-character action of "speaking the secret name of fire." But the book doesn't do that. And I have to assume it was an intentional choice. There must have been some behind-the-scenes discussion about Tome of Magic's potential for inspiring homebrew settings where they made the conscious choice to just not mention it directly.
It's part of a trend I've noticed in the game, going back at least as far as the middle part of the Dark Sun metaplot, where the official products seem really reluctant to split the setting. You can't just have a self-contained world, off doing its own thing, that just so happens to use the D&D rules. No, every new thing that's introduced is part of the same world, and at most you'll have an explanation for why the different parts of the world do not interact with each other (or, at least, why they haven't up until now).
It speaks to a fundamental disconnect between myself and the game's creators about the purpose and nature of the game's content. I always viewed things like new classes and creatures as a kind of cafeteria menu. In the process of building a world, I'd take a little bit of this and a little bit of that and I wouldn't use everything all the time, but even the stuff I wasn't using had value because maybe in a future game, I'd use a different set of ingredients in a different combination. By contrast, a lot of the community (and this has been a major source of friction for me, over the years) seems to treat new content as a dish that has been ladled onto their plate whether they like it or not. If they don't like a new thing, then that's not just an unused option, it's an active problem they have to work around.
I used to think that the second opinion was just a matter of griping by reactionary cranks, but I'm coming around to the notion that the books encouraged it. Earth Genasi paladins are indisputably canonical, but the book says they're rare, so you have to ask your DM if they're allowed. Or, to use an example more fitting to the book at hand, the churches of Hieroneous and Vecna will put aside their differences to persecute users of Pact Magic, and that's why you may not have heard of it until the DM decided to introduce it into the game.
Overall, I think Tome of Magic ranks pretty high on my list of favorite 3.5 books, precisely because the it's so much better as three new items on the cafeteria menu than it is as an expansion to the core. Like, True Name magic doesn't work because the way its DCs are calculated means that you get worse at your job as you advance in levels (and not just in the sense that high level utterances require higher rolls than low level ones - if you're an unoptimized character and you want to use the level 1 healing word on yourself, you have to roll an 8 or higher at level 1, but a 13 or higher at level 20 . . . assuming you have access to the item that gives you a +10 to your checks, otherwise it's flat-out impossible), but even to the extent that it does work, it would be absolutely unforgiveable to allow players to use spells with a Truename component. You know the thing people do where they have the true name of an enemy and they speak it as part of a terrible curse that utterly unmakes them, as if they never were? That's a Wizard ability. Truenamers can't do it. Which is maybe low hanging fruit as far D&D 3.x criticism is concerned ("oh, yeah, wizards can steal other classes schticks, but it's supposed to be balanced because they can only do it a limited number of times per day"), but it's only trite because it's true. Tome of Magic is a much stronger book when it stands on its own.
Ukss Contribution: I kind of like the truename wand that's built to work only on a specific person, but I feel like, given the importance wands have to the Ukss setting overall, that a Wand of Fuck That Guy in Particular would have a far different feel.
I also really liked the vestiges as a group. They had that "Biblically accurate angel" thing going on, where even the relatively benign ones were strange and offputting (one is described as a wheel made of lion's limbs). If I were to pick one to single out, it would have to be Focalor, the Prince of Tears. His overall appearance is relatively tame - a handsome human man with "griffon's wings" (and no, I don't know why you'd describe a winged character by citing a creature that notoriously has the wings of an entirely different creature), but there's something about a cosmic being that's constantly crying that really speaks to me.