I was thinking: the list can’t be all that difficult to come up with collectively, can it? The ”divide the fandom” piece isn’t the limiting factor considering that all “horror-adjacent” IP’s seem to divide the fandom. It should be easy for a bunch of HHN junkies to muster up a list of “horror-adjacent”properties. That leaves the difficult piece as realistically weighing whether it’s large enough to headline. To me, a few obvious properties that fit the bill on popularity are (and keep in mind, I’m trying to keep it loose with the “horror-adjacent” description with the expectation of debate):
1. GoT - Nope. The ship has sailed at this point.
2. Witcher - Most Possible out of this list. Some of the monsters and creatures are damn scary.
3. Goosebumps - Unlikely due to seemingly contract hurdles.
4. Scooby-Doo - TOO Family-friendly.
5. Harry Potter - Nope. Dark Arts at IOA is what we get.
6. Jurassic World - Nope. The current parks are how they wanna rep the franchise.
I think something that some of us need to keep in mind is that the recent "Horror-Adjacent" properties like Ghostbusters and Beetlejuice are two of the most popular IPs of the genre and has had lasting appeal over 4 decades (and are more than likely a big part of the childhood of HHN creators & designers). So Horror-Adjacent is still horror, just not in your face about it like a Texas Chainsaw or a Scream would be. Not to mention, while they were received in a mostly positive light - it also wasn't the slam dunk like Stranger Things was (with the common complaint being "not scary enough")
Beyond that, we gotta think of how it ties to the event with relevance and is it a money-maker (appeal/headliner, merch, food & bev opp).
So while something like Coraline may be a fun house to see come to life and can fall into the "Horror/Horror-Adjacent"... the chances of that coming would be less than 1% IMO due to every other parameter. It's the same thing with Casper and Scooby-Doo. They may be great experiences, but they are very markedly a family-friendly IP and IMO would be a marketing nightmare. "Come see Casper the Friendly Ghost and LEATHERFACE CHAINSAW PEOPLE!"
And that's where the discussions start to become someone's wishful thinking and not actual speculation.