Midnight can be divided pretty neatly in half: Part one, where there are too many subplots to keep track of, and part two, where Valkyrie has to save her sister.
Part one: I was happy to not keep track of the subplots, because each of them was fun and the pages went by quickly, the book compulsively readable. I wasn't sure where all the threads were going, and the constant POV changes felt sloppy. I think it's important for authors to realize that when the POV changes (especially when the characters are focused on entirely different subplots in different parts of the world), the reader is briefly pulled out of the story, and has to work to sink back in. When you change the POV over and over and over again in a series of short chapters, the reader essentially never gets fully immersed in the story. But still. I was enjoying part one for what it was.
Then part two seems to be when an editor was like, "hmmm we need more centralized Valkyrie/Skulduggery bonding stuff" and Landy pulled something out of his butt. I appreciate that Landy took a break from his go-to-plotline, the classic WE HAVE TO SAVE THE WHOLE WORLD, IT'S IN DANGER LIKE NEVER BEFORE. There are only so many times that you can have a megavillain who is somehow even more powerful than the last all-powerful megavillain. I made up the word "megavillain" for this series specifically. Things started getting pretty silly by the time Darquesse came around. But here's the thing: Abyssinia's resurrection was such a big deal in book 10, and she was presented as super evil and scary, and her cold dead heart "telepathically" communicating with a worldwide host of villains was genuinely disturbing.
But halfway through this book she just...changes. Becomes a normal woman who's subtly made fun of in the Landy-esque comedy way. Also, I need to say it: I'm sick to death of all the bad-ass women in Landy's books wearing skintight clothes. Like literally all of them are essentially described as wearing latex bodysuits. It used to just be Tanith Low's thing, and I was like, "eh, whatever, there are a lot of women who are really different in this series, so I can deal," but now every woman dresses like that. We get it, Landy. You have a type. But you're also writing for kids and teens, remember? Many of whom are girls?
I'm not even sure what the point of red-bodysuit-wearing Abyssinia is anymore. The whole Skulduggery family subplot? It feels cheap and tangled. Skulduggery's entire character arc that led to him being Lord Vile was this: Mevolent killed his wife and child, and he became super evil in his post-ressurection grief. The idea that that super evil, unfeeling Lord Vile had a girlfriend? And the fact that Skulduggery's wife and child—his CENTRAL backstory for most of the books—are never mentioned in Midnight? Are you kidding me? Who even is Skulduggery if his backstory suddenly just doesn't matter?
I understand that there needs to be changes when you start writing a long series, but the key is to add to the world building without negating anything that came before it. Cassandra Clare pulls this off really well with all of her spin-off series to the Mortal Instruments. I actually thought Landy mostly pulled this off in book 10, as he focused on the world and politics of Roarhaven. It just...disintegrated in this book, but I think he has a chance at pulling things together in book 12.
So, onto part two: Valkyrie gets a phone call. Her sister's been taken and Valkyrie needs to save her. My problem with this mostly had to do with pacing. All the other exciting subplots are abruptly put on hold and mostly never returned to. As mentioned, I appreciate Landy aiming for a more personal plot—saving the sister, not the world. Exploring Valkyrie's vulnerabilities and the power of family and friendship, etc. Blah blah. Except all of this has been explored before, it established nothing new in her arc, and there was no reason for it to take two hundred pages. At one point the villain actually remarks on how damn long their fight is taking, and it felt like even he knew the pacing was whack.
Also there's a chapter that's basically just straight up stolen from The Matrix. I love Landy's homages to his favorite books, comics, and movies, but what makes those interesting are his little twists and inverses (Omen Darkly's brother is Harry Potter, but that's the point: it raises the interesting question of what would Harry Potter's younger brother have been like). This scene was just straight up The Matrix,, complete with Agent Smiths flooding out of a building and a lone ringing telephone booth.
Also, it seems like his own Demon Road trilogy inspired him the most in part two, as Valkyrie stopped feeling like Valkyrie and started feeling like Amber on her monster-fighting roadtrip. I really, really don't like the Demon Road series, and I didn't enjoy feeling like his two series were bleeding into each other.
Notes on social issues: I used to be really charmed by Derek Landy's little feminist sidenotes, like when the zombie Scapegrace becomes a beautiful woman and learns that getting catcalled isn't fun. But I guess I'm older now, and now it just feels like I'd rather be reading a book by a woman instead. Every time the Feminism 101 stuff happens I'm reminded of when my well-meaning male friends learn something really basic about gender dynamics and excitedly "teach" it to me, and I have to sit there and smile encouragingly like a school teacher while suppressing my rage.
At least Never's representation was better this time around. In book 10 Never's sole character trait was their genderqueer-ness, which isn't even a character trait. Every time they were in a room Derek Landy had to emphasize what gender they felt like in that scene. My friend (hi Rachael) hilariously said it were as if he were pointing a big, lit-up arrow at his own book and going, "Look!! I included a gay!!!" Never actually has the beginning of an arc in this one, and Landy seems to have cooled down over the genderqueer thing.
I can't believe I'm writing this last, because it made me roll my eyes the hardest: Derek Landy, you can be inspired by comics and movies and books and stuff, but stop using the plight of real marginalized people to inform your plot. I thought the fantasy genre was over the era of using magical creatures as allegories for real marginalized groups. The magical creatures in Midnight are actually mortal, brought in from an alternate dimension, and they're clearly supposed to mirror real life refugees. But there aren't any like, actual Mexican or Syrian people, et cetera, on the page. And I don't want there to be, because I don't trust Derek Landy to write a person praying Fajr. Yikes. Just don't write about refugees in such a shoddy way. Oy vey, oy vey, oy vey.
Also, the Trump stand-in is hilarious, but it's very obvious Landy never had an American go through President Flannery's dialogue. Flannery...does not sound American. It was hard to read his dialogue in an American accent, even. Flannery ends sentences with "eh" and interrogative words (e.g., "He did, did he?") in precisely the way my Irish and English friends do. Lol.
This has been a disorganized and wordy rant. Tldr: The book was what is was.