There's a lot of world building errors as well. Like:
Ayup. If we take the first season at face value, the problem was already widespread by then. But that I imagine created locale/framing problems, so they collapsed everything down to pretty much just one site in S2.
Also they really flubbed the monster:
Agreed. Some generic long legged thing they call the Shadow Monster stinks of the basest level of idea mongering out there. When people's big bads are formless monsters, yeah your instinct is to call it Lovecraftian but these days, with the tropes so played out, it just strikes me as lazy. "Oh yay, another formless shape shifting terror." It's not like the Demogorgon from the first season was an amazing monster or anything but at least it had some character.
Basically all the monsters in Stranger Things have struck me as an adult version of a Saturday morning cartoon. That's the level of thought and execution that's gone in to them. I blame Lost, personally. Ever since the fucking Smoke Monster people think a formless, unintelligible evil jumble of shit makes for a good TV monster. It doesn't, folks.
What really clinched it for me is when they go back to the D&D manual (their token "this is a nerdy show" moment this season) and start describing a Mind Flayer. "Oh it thinks its a superior life form and wants to dominate everything." Like that's even remotely what this thing has been doing up until now. The whole ecology of the Upsidedown would have been a GREAT place to spend some of that writing effort, digging into what this stuff actually is and what it actually wants. But no. Instead the writers lazily just said "it's an intelligent chaotic evil monster. Cut. Print. Let's go have drinks."
And storytelling wise... Man:
For sure it has pacing issues. And as for characters, every new character is there to serve a specific purpose rather than being more well-rounded and interesting.
-Max fills up the female quotient both for the party and the viewing demographic. Her role is to be relatable for the audience since she's new to all this, her incredulity is supposed to be how we'd react to all this. She's also there specifically just to create conflict in the party.
-Her brother. He's there to make you sympathize with Max and grind down her edge to relatable levels. He gets a little more well-rounded as it's shown he's a product of his homelife, too. But still, he's basically there as the teen heartthrob asshole sometimes bad guy.
-Bob. Comic relief and sacrificial lamb for the plot. I was actually starting to like Bob when he began taking an active roll in things, but as soon as he was like "no, this requires computer programming skills so I guess I have to do it" I knew he was fucked.
-The Doctor. Thought he was supposed to be the main villain but it turns out that wasn't the case. Kind of a confusing character, he spends a lot of show vacilitating between being a company man and actually caring about the problem. It gets settled eventually but it made for kind of a disjointed character throughout the series. I figure they knew they needed the face of the "conspiracy" after Poppa was killed, so, they picked him. Probably 100% based on his performance from Aliens where he's essentially playing the same character.
And yeah, other than Jane, all the other existing character interactions feel flat. Will just has shit "happen to him", he's one of those characters in the series. Mike spends most of the season just being surly about everything to everyone. Dustin and Lucas' interactions don't have that childlike quality anymore, it's all a vehicle for fucking pre-teen relationship drama. (Dear writers, these kids are way too young to have you make 50% of the plot be about, essentially, sex.) Dustin in particular just gets a bunch of goofy, self-indulgent moments in the plot because I guess that was easier than writing good, effective dialog and scenes with all the characters. (Notice how the least effective parts of the show are when the party is split up each doing their own, almost unrelated thing?) Everything having to do with Max especially, due to the actress, just feels really fake and forced. And Joyce....they took the previous season's theme of the desperate mother who will do anything to save her child, who can pick meaningful patterns out of gibberish that most people ignore (someone CLEARLY had a mystic mother they're basing Joyce off of) and they just......did it all over again. Will is in trouble, again. Joyce is freaking out, again. Joyce plucks meaningful details out of the chaos of the story and connects the dots to put everyone on the right track, AGAIN. You kinda felt that with Bob around that Joyce as a character would change but....nope. Bob is literally tacked on to the existing Joyce character and themes and is shed by the end of the show.
The Jane-specific storyline kind of worked. But it also felt like a deliberate distraction from the main story. Like "oh let's leave this episode on the cliffhanger everyone has been waiting for....then cut to an entirely different city, storyline, and characters so Jane can learn a moral lesson then return to save the day." On the one hand I kind of liked the characters and the character development going on there....but on the other, it felt like someone making this went "we have an entire episode to fill still, what do we do? I know! Let's tell a morality tale about revenge and super powers. That should kill some time."
Because let's be honest: what did any of that actually accomplish, the ENTIRE Jane arc? Nothing. She meets her mom, she meets another test subject, and then she realizes she only cares about home after all and goes back to do what she was ready to 4 episodes earlier. It's an arc that has almost no point and no pay off other than seeing her with dressed in black with greased back hair, I suppose. Oh and her screaming and "using her full power." Ugh.
All in all, ST S2 feels like it could have cooked for much longer than it did. It feels like made-to-order television. And S1 didn't feel that way.
Put another way, it feels like this was a show run by producers instead of writers. All the beats that made ST S1 special are just thoughtlessly recycled. Almost like the things people thought the most about were what iconic 80s song should back up what scene. The season simultaneously takes too long with setting context and establishing characters, and not enough time on the actual action or important plot movements. (Although to be fair, Episodes 5 to 8 where people are actually doing things and figuring out solutions to problems vastly increases the show's entertainment value, compared to what you just sat through.)
I can safely say, before even watching the finale, that I don't need a Stranger Things S3. Not unless they actually do something different. There was so much missed potential in Season 2 that it's hard to not feel like it was all being phoned in.
I sort of almost expect a spin off ST series based on all the weird kids that have gotten lose in the world. But lord knows we already have enough primetime quasi-superhero shows already, I don't think it would do terribly well.