Will Byers has been through enough, hasn't he? He spent one year trapped in an alternate barren Hell dimension where he was being cocooned by a freaky monster and had tentacles going down his throat, then spent the following year vomiting up baby monsters, briefly flashing into the Upside-Down, and finally being possessed by a malevolent hivemind that used his body to cause death and destruction.
And most importantly, Joyce gets to spend A TINY BIT OF TIME not freaking out nonstop over the mysterious happenings around her poor son. Joyce deserves a break.
One of the few big setups the writers left for season 3 was - weirdly - that Billy and Mrs. Wheeler are totally gonna bang. It's no surprise Mrs. Wheeler's lookin' for some young hunk to bone - Mr. Wheeler is hilariously the most negligent, oblivious father/husband ever witnessed on TV. Plus, if Mrs. Wheeler and Billy are banging, Billy will probably be a lot more relaxed and less interested in constantly harrassing Max and Lucas, which would be nice.
"I may be a pretty shitty boyfriend, but turns out I'm actually a pretty damn goodbabysitter." - Steve Harrington
Steve truly came into his own in season 2, reluctantly taking on the role of babysitter to our precious wayward Goonies - mentoring Dustin in the ways of love and haircare, protecting Lucas from bullies, trying to fight off Demodogs, and allowing them enough slack to help create a diversion against the monstrous hivemind invading our dimension. That's the mark of a good babysitter - they're firm, but fair.
Hopefully season 3 leans into this hard - these kids NEED Steve's protection and guidance. Think about all the pickles they've gotten into in two years, and how many problems could have been avoided if only they'd had a large-haired guardian with a spiky baseball bat watching over them.
Note: Kali and the gang died on the way back to their home planet.
I say Will Byers has had it rough, and he absolutely has - but that's nothing compared to the lifelong hell Eleven has had to endure. Being tested and prodded for literally her entire life, until she was mentally pushed to a point where she tore a breach through the fabric of reality itself, then had to contend with the monster that was unleashed, the pain it caused to all sorts of people, and being made responsible for undoing the damage...ALL BY HERSELF. Even in her one year of not being held captive by a lab that saw her only as a test subject, she was still BASICALLY held prisoner - but at least Sheriff Hopper was a bit nicer than "Papa."
All Eleven wants is something resembling a normal life - hanging out with friends, learning at school, and NOT having to tap into her unnatural powers to prevent armageddon because everyone else is basically useless in that regard.
Okay, sure - we "saw" Bob and Barb's completely, 100% dead corpses. Sure. I'll accept that. BUT - think about the multitude of comic books, movies, and TV shows where clearly "dead" characters were revealed to have miraculously survived what appeared to be unquestionable death. And let's then imagine that both have been alive, but stuck in the Upside-Down (I know Bob died in the normal world, but maybe the Demodogs dragged his body into the Gate or something)...and have grown into battle-hardened warriors. It would be great! The two characters notable for being wholesome and unsuspecting but befalling to terrible fates come back as cynical, scarred, but very much alive badasses, wielding shotguns killing Upside-Down monsters left and right.
Alternately, just have two enormous golden statues where Hawkins Lab used to be of Barb and Bob, honoring their memory.
...also, man, really doesn't work out well to be a nice, chipper character whose name begins and end with a "B", huh?
THEY MADE DUSTIN CRY AND THEY DESERVE TO SUFFER. It's one thing to reject him (his hair did look pretty stupid), but they just HAAAAAAAAAAD to laugh at him and make him feel like a loser, didn't they? Well, if Bob and Barb have to go, so do these kids.
Gonna be honest - I like all of these characters too much. I'm sick of seeing them have to contend with terrifying horrors year after year - just let them have a nice time for a little while and not deal with anything supernatural. That last 15 minutes or so where it was mostly just characters we know interacting and reconnecting and hanging out at a school dance was SO NICE. Why can't we have more of that?