Doing some more brainstorming, whatever theme we decide to go with, I really want to see a full fledged attraction (sort of like the Edison Square idea except an actual ride) somewhere in the street.
Continuing with my German Street idea, the architecture I'm thinking of would be something along the lines of this image:
Also, since every castle park disney has ever had always has one solid street, let's make it's more exciting by having a river bisecting the street. The river could hold a either a transportation ride similar to Discovery Boats at AK, or a raft ride through the dark forests.
In regards to shops, I think the street should be divided into different sections representing each area of Germany. Each section would have a unique offering. For example, one section could have a restaurant, another could feature a large shop, a different section could feature a ride as previously mentioned, etc etc.
The park would have to have a train, I mean, what's Germany without trains!? There could be multiple dioramas along the route showcasing either something historical, or regarding the nature of the land.
I'll probably come up with more ideas, but this is what I have so far!