Dragging up some old commentary.

Originally written in response to a request for critique:

SD's biggest problem as an HPMOR sequel (in my opinion) was that it simply wasn't in the same genre. Like, it didn't have complex tangles that the reader was meant to be able to unravel, or rigorously defined rules that the reader was meant to game, along with the characters. It didn't "use" rationality such that the clearest thinkers would come out on top specifically because of their clear thinking, and it didn't provide object lessons that were any more specific than "generally plan ahead, okay?"

Instead, it was just high fantasy with a modernist/transhumanist protagonist. Which is pretty neat, but not in "the spirit" of HPMOR. It wasn't rational fic, in my estimation.

As for its qualities as a work of fiction generally—it did a lot of things right (very cool spells, neat dramatic history, decent intrigue, good skipping around in time). Where it missed, for me:

—Much of the plot felt random or just-because, as opposed to emerging from the "first principles" of the universe. There's an OSC quote I really like that goes something like "fiction isn't about what happened, once—it's about what happens." A lot of the events didn't seem like they were in line with the flow of reality, like they were the sort of things I could nod along with and say "Yeah, it would happen like that!" For instance, the plot with Harry and Draco pretending to have a falling out and then just neatly tidying up the world into one largely unified package ... that's good enough for Brandon Sanderson fiction, but not for a story that purports to be realistic-fantasy.

—Chekov's Gun misfires. The amount of words spilled on (e.g.) the spaceships and the pocket worlds and Neville/Fred/George and the whole American scene just ... didn't really seem to pay off? Like, the spaceships paid off because they allowed Luna (off-screen!) to take the Mirror into space, and the Neville/Fred/George bits paid off because they allowed Neville his (exquisite) badass moment, but both of those climaxes could've been purchased with fewer words, or alternately could have been better fleshed out and felt more important, to match how much time was spent on them earlier on. Similarly, Hig never really mattered except as a random background character ... we could have replaced him with a different guy or a woman or a magical creature or a lump of furniture, and it wouldn't have changed the plot (i.e. his specific personality and motivations didn't really affect anything, and therefore I conclude we spent too much time "getting to know" him).

—The climax was incredibly, incredibly dumb. I'm sorry, I know that's not constructive, but it was such a letdown, Harry's tone was off, Merlin's behavior matched that of an idiot who'd never thought things through when it should've matched that of a cautious immortal who's spent literal centuries thinking about all of the consequences of all of his actions, it felt (to me) like the scene at the end of Avatar where all of the humans leave as if that's a happy ending, as if they're not just going to come back and nuke the place from orbit. It makes no sense for Merlin to both have failed to put two and two together for the past decade, and also to be the kind of rational quick-updater who will just nod and walk away. It's not consistent, and if it was going to be consistent, the conversation should have been 3x longer and more nuanced, allowing Harry to actually, y'know, be persuasive instead of basically just pulling a Doctor-Who-on-Trenzalor and saying "I'm so awesome you don't even KNOW how you're going to lose, but it's definitely a foregone conclusion, so don't even bother to try." An actual rational Merlin (and here I just mean a level-one rational character with consistent motivations, not even a particularly intelligent one) would either have not been there in the first place, or would've just killed Harry anyway, and if the point is to show that Harry leveled up Merlin's awareness and perspective during the conversation, then that needs to be far better underlined and far better justified, given that he's rationalsplaining to someone who's survived for over a thousand years.

—Pacing, but it seems like you guys [beta readers] are already aware of/on top of that.

In general, I posit that the problem was poor back-chaining. Like, either he didn't really know how the story was supposed to end, and kind of wrote himself into corners, or he knew how he wanted it to end all along, but didn't do enough diligent work along the lines of "okay, these are my themes, this is the end state of the board, this is the message I want to get across/impact I want to have on the reader, now let's work backwards and not do anything just because it seems cool."

Had he done so, the climax would've been larger and fuller, extraneous storylines would've been tightened and streamlined to make room for the stuff that really matters to rise above (thereby focusing the readers), and we would've known which aspects of characterization to pay attention to and which events had real consequence and should be concerning. Another OSC example ... he talks about how you shouldn't start a story as a mystery, and then end with the widow falling in love and getting happily remarried without ever solving whodunit. There's a kind of promise you make, to your reader, that the initial questions you pose will be the ones you answer in the climax—that once you've told your readers what your story is about, they'll know when it's over, because they'll feel closure and resolution.

What was SD "about"? It's hard to tell. Was it about convincing Merlin that magic should be allowed to continue, and isn't an existential threat? Was it about overwhelming Merlin through the use of rationality, even though he couldn't be convinced? Was it about the friendships of Harry, Draco, and Hermione, and how those friendships deepened and changed? Was it a Shadow Puppets-esque, Tom Clancyish story of politics and intrigue, telling the tale of the unification of the magical world? Was it about the merger of magical power with scientific principle, and the first steps into a brave new frontier?

I think it tried to be all of those things, and ended up being none of them, where if it had tried to be one or two first and foremost, and let the others play backup harmony, it would've been far, far stronger, as a story. I would've liked to read any of the stories listed in the previous paragraph, pure and unalloyed and done with the skill this author has at his disposal (because he does generally know how to write, even though he's not an expert yet; the Egeustimentis chapter in Harry's head is the scariest thing I've ever read). If it's a character story, it's a character story; if it's political drama, it's political drama; if it's high fantasy, let it be high fantasy. And most particularly, if it's intended to be a showcase of rationality, it can't make the mistakes SD made (the number of enthusiastic fans on reddit notwithstanding).