This is an event for EVERYBODY. Not just you, me, and the thousand or so people on these forum who pour over the details and anazyle every tweet and every frame of video released. It's for thousands and thousands of people who attend, many for one night, who come in with no understanding of the crazy backstories for the event. What do you think is more rewarding to them? Something they are familiar with and can "live the movie" as is the point of a movie-based themepark, or something awesome but that is really hard to figure out. Why does this house have cowboys and ghosts? Why are Penn and Teller nuked? Why does this building have lots of water and Nine Inch Nails blasting? I thought this was supposed to be an Alice in Wonderland house, why are we in an asylum? Why are there monster nurses in a war? Etc. If you go in knowing the back story, sure, the originals are fun...but EVERYBODY knows the backstories from the movies. Look at in reverse, if you had never seen a Saw movie, the previous house (and I'm assuming this year's house) would make zero sense. What the hell is that thing on that lady's head? Why is there a puppet on a tricycle? Why did this idiot crawl into a room full of barbed wire? Ash vs Evil Dead is the same thing....why doesn't this guy have hand? Why would a chainsaw and a shotgun be his choices of weapons, that's stupid! (you'd have to have watched the show or movies to understand that Ash being a moron is part of the story and the charm...without context it looks stupid) What the hell is up with this puppet? How is a puppet scary? etc, etc, etc (don't want to spoil anything from the series, but you get my point).
A known property enhances the experience for most people. There are obviously exceptions, but it's certainly true. A house that takes 3 minutes to walk through has exactly 3 minutes of context for you to figure it out unless you pour over the website, tweets, forums, etc, etc, etc. Maybe you have a one paragraph synopsis if you read the blog. A movie-based house has at least 90min worth of context before you even walk through the door so you go in understanding the storyline and get to live it.
A movie themepark with almost NOTHING original in it (is there anything original in the park now other than Rip Rocket? Dueling Dragons is closing and also somehow considered Potter-related now, everything is IP based) has a seasonal event...it SHOULD be movie based. It would be like Sea World having an event based on lions and tigers or Disney World having an event with Looneytoons characters.
This isn't settling, it's evolving. It's living up to the (perceived) mission statement of a Movie Theme Park that has active TV studios on property. It's a success story that the event is so well respected in the industry that people who are VERY protective of their IPs are willing to let a theme park take over their babies and create a fluid and evolving experience.