Storywise, there's just so much I find nonsensical or just uninspired.
What I liked: Scarecrow uniting the villains in one last ditch attempt to bring down Batman in a post-Joker Gotham. The main driving force behind the plot works in a Knightfall-esque sort of way, it makes sense that Joker would have always kept the villains divided because of how much of a singular threat and agent of chaos he was. Scarecrow works as the big bad on account of his thematic ties. He also doesn't go and recruit every villain under the sun or villains who feel like they would have zero stakes in the story (those being better left for side stories).
What I didn't like: Starting with what I hate most, Joker blood corrupting people. I fucking despise this. It's not the first or the last time, we've seen this thing. I cannot get over how contrived it feels nearly everytime. It's never heavily leaned into supernatural when it should be; the superscience that Joker's DNA could thoroughly corrupt another person into being Joker-like is just stupid. The best alternative has always been Batman Beyond's take of it being a superscience microchip that had Joker's thought patterns and memories.
Arkham Knight's identity. They come up with an interesting design for an anti-Batman among hundreds of anti-Batmen. Wasting it on Jason Todd, when they could have just made an original character or just use Red Hood from the get-go (or any of the other anti-Batmen like Wrath or Hush).
Alot of the side stories. They are just useless and don't fully utilize the antagonists of them (except for Mr. Freeze). They're just mostly dead-end plots that do nothing for the greater Arkham mythos. Hush was wasted, Blackfire was wasted, and I don't even know why the Ra's Al Ghul story existed.
The Knight's identity was blatantly obvious in the marketing run-up. Solid looking design, but it was super obvious it was Jason. I don't have a huge problem with that, for in universe, but it was a weird part of the marketing.
The Joker Blood thing was so stupid. And Joker was so much of a crutch for them. I played the series in order back a couple of years, I think the worst use was actually in Origins. He should have been a side story (the Tower Climb was really good) and stayed there. I even thought, later into that game, that their lack of confidence in other villains was kind of noticeable.
Hush was so badly used in Knight. Massive drop of the ball there.
As great of a villain as Joker is, I hate how every Arkham game always had to go back to him. I enjoyed the first two games and was really excited to play Origins based on the trailers and the fact that we were finally getting a different main villain, and one that wasn't as popular as many of his other more well-known ones with Black Mask. Figured they had a really good premise going with him and the others. So it was incredibly disappointing to learn that "PSYCHE! IT WAS THE JOKER ALL ALONG" before I ended up even buying it. Completely killed my interest, and while I do eventually plan on playing it when I get around to it, I still haven't to this day because of my disappointment, nor have I played Knight yet either.
The Batman franchise has one of the best cast of villains in comic book history, and yet Rocksteady continually had to default so much back to the Joker being behind things. Such wasted potential.
He didn't need to be in City. That's actually were he was used worst, I feel. He took up way too much of the game and the Joker dying wasn't that interesting, as they hadn't established the relationship that well in-series.
Which is why it was almost assuredly a mandate from Upper Management at WB. If he was put into City late in the cycle, that would make a lot of sense.
It just showed a lack of confidence in their own product. They're so worried of the game not selling well that they think hamfisting the Joker in as a way to ensure audience attention is a great backup plan in case no one cares about Scarecow at all, which is beyond absurd considering the Nolan trilogy made Scarecrow more mainstream in the public eye. The lack of risk taking and playing it safe really did sully the rest of the Arkham games with their flip -floping commitment to making other villains the main star for once.
Scarecrow in Knight was phenomenal. For as drug on as that game got and the design problems, I honestly think the last 3rd of the story there (after the cloudburst) might be the strongest narrative part of the series. And, honestly, the fake out in Knight actually got me. The game was serious enough that it could have been the big dramatic point.
And the ending at least showed they understood the essence of Batman pretty well. They managed to make Batman actually terrifying.
It's hilarious the amount of coping they were doing about the "nuh-uh! It's totally not Red Hood!" and everyone figured it out the moment the first flashback scene of Jason Todd showed up.
Ra's is a perfect "central villain" but its a shame they had to finish it with the whole Joker storyline. Hush would have also been a great choice and they even were hyping people up with it in City but then his sidequest in Knight was super wasted. Sucks they wasted Black Mask with a Joker twist.
They just put out a TV series about the Penguin and it was so well received that it even won a Golden Globe for best actor with it now being called the "Heath Ledger" of Joker performances.
Penguin wasn't well used in the Arkham series, in hindsight. But, yeah, Knight's side stuff hit pretty weak. City's story was far more of a mess when you talk about it, haha. Oh, Talia in Knight was pretty bad as well.