Of course the pacing of the introduction is going to be different now, but it isn't necessarily a bad thing because it varies from the original iteration. I've detailed in an earlier post why this new queue actually
adds to the spookiness in the ride's first act.
I read your theory, and it's not bad, but there's one problem you need to address: inside, the ghosts are in a bad mood before they materialize and in a good mood afterwards. Incidentally, this accords with a lot of traditional ghost/spirit possession lore that the spirits are miserable while disembodied. You could argue that they are just play acting before the séance, but I think that's a little far-fetched. Look at the ghost trying to get free in the Conservatory. Just teasing? He sounds pretty authentically desperate to me. Compare
that guy with the bubble-blowing Sea Captain and you see the problem.
The Dread family murder mystery thing is just a small part of the queue. It's purely atmospheric, and there's no good reason that a little character development of the ghosts would "de-personalize" the HM experience.
If the new props next to the HHG's are any indicator, the Dread family is going to be stuck into your face all through the ride. If some ghosts are given intriguing and complete little histories, the ones that aren't automatically take a back seat. I don't see how you can help that.
You posted, in the Doombuggies forum, "The spirits demonstrate an ability to warp and alter the very fabric of the building...and they seem especially apt to play games with the artworks." If the ghosts can make busts sing, rooms stretch, and allow us to see through a ceiling, among other things, certainly these tricks can be pulled with objects more dimensional and tactile than paintings. The crypts are most likely distorted from their true forms, and perhaps the Dread family busts have taken the form of caricatures of their "corruptible mortal states", like the stretching room portraits. As such, the art style of the busts and crypts is consistent with pieces inside the mansion.
All this can be shown without making "Is it your imagination?" a meaningless question, and none of it comes at the expense of the mystery of the HM. Even if our suspicions of ghosts being real are confirmed right away, we do not see the metamorphosis with our own eyes and have no reason to suspect that the ghosts have this ability until the stretching room. When we do witness the transformation, we are still left questioning our imaginations just as before. Worse yet, as I detailed in the linked post above, there is an added element of fear that wasn't present before the queue - fear that the ghosts inside aren't as harmless as those outside, fear that, lulled into a false sense of security by the queue, we've been lured beyond the point of no return.
I have a hard time following your argument that "Is it your imagination?" is left undamaged. The stretchroom question leaves you in doubt as to whether any of the distortions you see from then on are real or imaginary. Well, if you get your face too close to the crypt bookcase, you'll get a bloody nose. Pretty decisive answer to the question before it even has a chance to get asked. Also, your entrance into the place evidently causes a stir. Note that the GH is paying particular attention to
you, he's talking to
you. The busts turn and follow
you. The possessed raven has his eye on you and even follows you around. In other words, all this warping and twisting of rooms and artworks is not just diddling around to pass the time but has a purpose: they're trying to scare
you, to disorient
you. But if the artwork and crypts in the queue are examples of the same kind of activity (right out in broad daylight?? and left that way permanently??), long before you ever came around, that doesn't make much sense (to say nothing of poor show pacing). If this was done to scare previous visitors (let's say), you would think they'd "put things back" when they were done. And besides, all of the "real or imaginary?" stuff indoors is meant to
scare you and
unnerve you (yes, even the stretchroom portraits: that's pretty macabre humor). This queue stuff, on the other hand, couldn't scare a Smurf on a dark and stormy night!
I don't buy that these new additions remove the HM from the real world anymore than it already has been. Even with the quieter pre-interactive queue intro, there was always an element of ghostly silliness. I don't see any difference between gravestones with darkly humorous epitaphs and the new busts in terms of "cartooniness".
The macabre epitaphs are not one bit goofier than real-world "boot hill" type epitaphs, so I don't think they're cartoony at all. But in the queue, evidently that's really supposed to be what Bertie looked like, sea serpent and all (unless you subscribe to your theory that the ghosts came out here and did a number on it and left it that way permanently, which seems like quite a stretch, as I've just explained). Bertie is exactly in the same style as ax-headed George in the widow painting, but that's the result of ghostly expansions of a normal-looking portrait. It just seems awfully hard to me to be standing there next to this new bust and use that same explanation to account for its unrealistic appearance.