Despite them wanting to make it a Theme Park, the future plans to replace the Plunge ride is more of the same, spinners and coasters. They need to add more dark rides.
Also, I don't agree with Mystery Lodge having the best queue at the park. The entrance is nice, but then you're led into a relatively plain cattle pen. Calico Mine Ride, Timber Mountain Log Ride, and Jaguar all have queues that are themed throughout, and I'd say all three of them are better than Mystery Lodge's.
Pepper's Ghost was originally discovered by science before being applied to the theater. Jim Steinmeyer has a great lecture on the subject. It's an effect that is still used widely today throughout stage and themepark attractions (Haunted Mansion, Blue Fairy in Pinocchio dark ride).
And as Robert mentioned there is another astonishing effect in the show. I won't talk about it here so as not to spoil the show and effect, but it's something to see. It's classic and well done and yet a powerful effect.