I think that the idea of an adventurer's shop/inventor's shop, etc. in Main Street is fantastic. For Frontierland, I favor the more serious, Paris-esque aesthetic. A fleshed-out backstory and connected attractions, the whole nine yards. (Note: I want to keep the quasi-tradition of the Haunted Mansion being in a different land for every park. My thoughts are geared towards either Main Street or Adventureland.) Speaking of Adventureland, I do realize that some exotic locales appropriate for Adventureland might be suited to a second gate (Which makes me think that we should at least decide on a theme for a second gate. I really don't think we should even worry about a third at this point.) Adventureland, to me, is most effective when it explores several separate locales. Glad we agree on Fantasyland. Also, for Discoveryland, I want to avoid any attractions that do not fit its theme. No Buzz, Star Wars (I'm thinking second gate), Marvel, etc.
In general, I want to capture the best of each park: the intimacy and charm of Hong Kong and Disneyland, (as well as the attraction count of Disneyland), the grandeur of the Magic Kingdom, the elegance and sheer beauty of Paris, and the spectacular maintenance of Tokyo, along with its great unique attractions.
I think we should work land-by-land, rather than holistically, while still keeping in mind the sense of the entire park. Given that, we should begin with Main Street (as well as the hub and maybe the castle.)
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Main Street
My fleshed-out plan for Main Street would be to have sort of a mix between 1920's and Victorian; that is, there would be unified, transitional Victorian architecture throughout, but one side (the side nearest Discoveryland) would be more modernized and Jazzy, while the other, nearest Frontierland (I'm thinking of using Paris' layout, roughly), would be more rustic and Victorian. A compromise between the excitement of the 20's and the charm of the Victorian age.
For attractions, I think that, of course, barber shop, vehicles, train depot...the traditional things. However, on one side, I would like an electric railway that runs through the sidestreet and the arcade. Not necessarily visible for most of the length of Main Street, because that would be distracting, I think.
I don't think we need to worry about shops, restaurants.
The hub should be circular and tree-lined, like the traditional Disneylands. I do want the entrances to the lands, however, to be more spread-out. Especially in Anaheim, the lands are crowding in on the peacefulness of the Hub. Also, I love the idea that Paris has of moving the Plaza stage over so that its not in the way of the bridge.