In discussing season 2, there's much talk about the pacing. Rightfully so, it's mile-a-minute stuff. And there is also reference to the fact that there probably should've been a season or two extra, which is also entirely reasonable.
But I feel like this sort of discussion can distract from the fact that season 2 was not very efficient with the time it did have, especially when compared to season 1. Yes, they had a lot to cover in a short time with the story they chose, but they absolutely could've put the time they did have to better use.
Season 1 of Arcane is magnificently efficient. There are very few extraneous scenes, or even scenes that "only" work for one character. The script is multithreaded, at any given time several threads are being fleshed out. This is not so in season 2.
For an illustration of this from season 1, take the Hextech Demo to Heimerdinger in E4. I could've chosen a whole lot of other scenes, this is by no means unique, but I'm just particularly fond of this one. This scene, on its face, is just fanservice slop. Everyone gets to say "omigawd it's Viktor with his deathray and Jayce with Vi's gauntlets. It's the thing from the thing, I clapped". But the scene does so much more. The actual inventions display character, with Jayce's being less outright impressive, but more fully finished, more practical and more reliable. Viktor's is more flashy and scientifically impressive, but less aesthetically pleasing, less practical, and foreshadowing his later issues in the story, he has not done the work to make it safe. The inventions themselves show what should be expected from Hextech. Jayce speaking on behalf of Viktor establishes their dynamic, with Jayce running the people-stuff and Viktor staying sqaurely focused on his work. Heimerdinger's reactions and his response show that he's not a luddite by any means, but is far too cautious for either of the inventors. Jayce not fighting back more against his response despite Viktor's immense displeasure shows the beginnings of a rift in this mouthpiece-system, with Jayce not necessarily reflecting all of Viktor's views. And I could go on. It is a very dense scene.
In contrast, season 2 indulges in a lot of very single threaded scenes, culminating in the almost absurdly single-threaded 7th episode, which is completely isolated to the characters transported to the AU. Jayce in his hole develops Jayce in his hole, and that's it. Ekko stumbling around with the AU people develops Ekko, and a bunch of people we will never see again.
The characters of season 2 are also bizarrely inefficient, especially when contrasted with season 1. Season 1 wrote character into the margins of the script. Take Marcus. He is a means to an end script-wise, supplying reasons as to why Vi disappeared for so long, why the enforcers are so incompetent, and why Caitlyn can't just walk across the bridge. He does not receive much screentime at all. And yet, they crammed in a well done character into this plot required role. Even his death, which receives almost no attention, is perfectly fitting for the character they built up. And his scenes develop other people as well. Silco, Jayce, Caitlyn, he's not just isolated.
Compare that with season 2. There's a lot of easy targets in season 2 for criticism. Take Smeech. He was a relatively charming character in E2 who received a few scenes and quite a bit of dialogue. He was built up... and then died. That's all folks, it's over for Smeech. The other Chembarons pique the interest of the viewer for what time they do appear, and then they get murked in a music video, never to return. Never mind the goonsquad Caitlyn brought along as the Task Force, who receive bizarre amounts of attention for how vacuous they are.
And then there's Isha, who combines both of these problems. She receives exorbitant amounts of screentime, rivalling Viktor from season 1, and outdoing Vander. And she completely revolves around Jinx to the expense of everyone else. Silco she is not, she's running a 100% Jinx ecosystem and will not interact with the story meaningfully in any other way. And she's utterly hollow as a character, so she's basically just a vehicle for just Jinx characterbuilding. This is unfathomably inefficient. Putting her up against Vander or Viktor feels unfair, but it isn't. She could be a comparably deep character, but she's just someone to develop Jinx.
And finally, while this post isn't supposed to be focusing on the actual events contained within S2, and just the ways they tried to achieve them... God, some of these choices are manically inefficient. Like, did we really need FOUR separate and distinct Viktors (Jesus, Space Satan, Mage, and True)? Would we not have been better off with one single Viktor, and developing him the whole way through, instead of starting up a new guy every few episodes? And then there's the incessant music videos, which drain time away from more cerebral scenes and absolutely do not carry the same weight as actual real parts of the show. If the police brutality in Paint the Town Blue was not a couple frames of a highly stylized music video, the events would be regarded very differently. And if Hellfire wasn't a completely bizarre musical tone for the events shown, the gassing of the Undercity would've been regarded more soberly. But they just keep coming, in every episode, without fail.
I won't deny that achieving everything they wanted to achieve in season 2 in just 9 episodes was very, very difficult. Even with season 1 tier writing, it would've been somewhat rushed. But it would've been much, much less rushed, because they could've done a lot more with less.
