The Disneyland railroad, with four stations, has a station on average every 500 meters of track. At Magic Kingdom, which has three stations, it's on average every 800 meters. And Disneyland is already a smaller park to cross on foot. It seems like a no-brainer to put a station in Villains Land and bring that average length to 600 feet and give tired guests an option to get from the far back of the park to the front, so they can leave without clogging walkways.
Disneyland also has two incredible dioramas back-to-back, and a diorama would be a great addition to MK's railroad in Villains Land. Not only would it be a cool, unexpected "plussing up" and provide some parity between MK and several other castle parks, but I think it offers a chance to introduce the thematic concept and backstory of Villains Land.
That is, Villains Land will undoubtedly be cool, but it's still a tough concept creatively to bring all the villains together in one realm and rationalize it story-wise. Sure, they can just lean on tropes and motifs and aesthetic design and hand-wave away any need to explain what the place is supposed to be and why it exists, but it will be stronger -- and it's in Imagineering's tradition -- to have a backstory.
But often these backstories, which serve to inspire the Imagineers, can go unknown by guests, leaving them confused by the creative choices in the land. Avenger's Campus is a perfect example: that weird mix of old industrial brick buildings and a modern sleek office park is meaningless and doesn't resonate (i.e., trigger warmth of recognition by guests)...unless you know the backstory that the site was once the location of Stark Industries, and by the way, you have to even know what that is, like Marvel fans do. Other than putting "Stark Industries" logos all over the land, they didn't leave much other evidence of that history (old 1950s rockets or flying cars or anything Howard Stark may have built back then that may be left over).
All that may be a bit of an aside, but the point is backstories are helpful, but Disney can get a better reaction from guests when they actually convey them, and not just use them as a design-process tool.
So, a train diorama leading into Villains Land (and hopefully leading up to a station) is a perfect chance for a diorama to give guests a rich taste of the land's concept and flavor. A narrator could say something like:
"As we venture into this shadowy realm of the Magic Kingdom, we drift off to a land of our fantastical fears and wild imagination. What if the scoundrels, villains, and rogues of enchanting tales had a place to call their own, where they could hatch their dark and devious plans together, shrouded away from the light of goodness and fairness. Do you dare disembark and explore these dark dreams? If so, try to keep your eyes wide for dangers, and don't fall too deep into the sinister slumber of Villain's Land that you don't wake it out."
This, for example, spins the land as a "what-if dream" and not compromising the story cannon of any individual IP. But it's a conceptual backstory and difficult to express through the physical design of the land. That is, it's not easy to come up with architectural, rockwork, or landscaping cues that say "this is all a dream."
A diorama, with special projection effects, along with narration allows that story to be told easier. Using similar techniques to the slightly psychedelic Heffalumps and Woozles scene in the Pooh attraction, the idea that we are falling asleep and having a scary dream could be created in this diorama. We could roll from Frontierland into a forest and in the diorama what initially look like a continuation of forest trees could start to transform into spooky trees right before our eyes...suggesting our "nightmare" is taking over. This would all have to be done at an all-ages level, but enough can be done to tell the story.
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