At least for me, the fun of a mashup is getting to see properties/ideas that would never be able to support a full house on their own. I loved Get Out and it has enough material for a room or two, so it would have been the only way to see anything from the movie at the event.
The current Blumhouse lineup is just so dull if true. Two films that have already have mazes (along with a scarezome this year), and if you told me Sinister was an Insidious spin-off, I'd believe you; it's just not that aesthetically unique.