On Hopper. Given the story arc between him and Joyce and the way he was "killed" off, I'm even more pissed with the writing for his character this season. Since day dot, Hopper's consistently been a bit of a grumpy fuck. For season three however, it really felt like they Flanderised him somewhat and so instead of just an edge of grumpy, it became his overriding character trait. For much of the season, he really was an unlikeable shit and whereas in the past I've wanted him and Joyce to hook up, this time around I was really, really hoping she'd kick his sorry manchild arse to the curb. The ending of the Hawkins part of his story felt half arsed and mawkish in its attempt to make him a bit more reasonable and came off as too little too late.
Tigger had a few issues regarding the suspension of disbelief and the cartoonish nature of the bad guys. The response I'd make to that is that if you look at the media properties that would've inspired those parts of the storyline, Red Dawn, Commando, various and assorted action films, these are big issues there too. Now I'm not going to claim the Duffer brothers are incredible geniuses, deliberately salting their "Red Peril" 1980s action film pastiche with the flaws of the genre. Rather, what I think actually happened is that in their desire to emulate it, they maybe underestimated a modern audience's tolerance for plot holes and characterisations that are these days, somewhat tired and hackneyed. Being true to the intentions of your pastiche is fine, but sometimes you gotta remember that the audience you're speaking to now, isn't the same as the audience back then. See also the minor controversy that's blown up around the depiction of smoking in the show. It's pretty much part of the same issue.
I liked Steve and Robin's arc. It was a nice subversion of the John Waters "geek hooks up with cool kid that s/he's loved from afar" trope. It's also nice to see a boy/girl friendship that doesn't involve shipping potential and it's nice to get some lgbt representation in the Stranger Things universe.
The monster this season was neatly done, pulling in elements from several sources to come up with something pretty creative. Yes, there was a zombie element to parts of it. There was also nods to Invasion of the Bodysnatchers, The Thing and The Stuff in its design. The scene where it called all its minions home to sacrifice themselves was particularly creepy. Stuff like that, where people either willingly or via mind control damage/kill themselves at the behest of a big bad really squicks me out. I also really liked the cgi work on it. It seemed to be rendered at a slightly lower framerate, lending it a little bit of a stop motion feel that had to have been deliberate.
Finally, what the fuck happened to 8 and her crew? Their bit last season really felt like a set up for more interaction down the track. I know they weren't popular with a lot of noisy people on the internet, but I really hope they weren't dropped for the show because nerd rage.