A good point...but a purely academic one, since the design aesthetic of the Museum of the Weird died along with the idea for the ride. I think the original point being made was that there is a current "look" to the mansion's outside and inside, and breaking that design ethic with things that are overtly different just feels a little bit like going to see the Mona Lisa at the Louvre but finding it framed with something tacky, unexpected, and altogether inappropriate to the art of the Italian Renaissance. I agree, designs like those would be great for something along the lines of the Museum of the Weird...but not for the attraction as it was actually built.
And for the record...I'm glad we didn't get the Museum of the Weird. The idea just strikes me as a little too "out there." I like the creepy-but-kooky haunted house ride that we got instead.
EDIT: Looking back at your post, I'm realizing you probably weren't trying to tell us that the mansion should be converted to the Museum of the Weird. I made it sound a little like that. I guess all you're saying is that the Burton-esque designs could have had roots closer to the mansion's history, which I'd say isn't far-fetched at all. After all, unused ideas do tend to sprout up again later.