The content could be very creepy, plus they have a ton of material that the house could be based on. Just because the material is cartoon based does not mean it couldn't be scary or even gory for that matter. But I really think its a mute point as I doubt they would do it.
I liked the Monster house last year, but it was essentially all the big name classics from Universal. But I believe there is Frankenstein and Dracula reboot coming out, so that is why I was thinking they might go with one of those.