Hi Klötenkieker and thanks for your question.
Plazas present an interesting problem for our flow simulation. Getting from A to B on a plaza is the same as going from A to B anywhere else on the path and that is already possible now and you can already make small plazas with a little trickery.
The technical challenge in a sandbox game like Planet Coaster is memory usage and how long the computation will take. The amount of computation of the flow fields grows with the surface area of the paths that the wave needs to propagate through. With a plaza we are dealing with very large surface areas (easily more than all the rest of all the path in your park put together).
We are as passionate about large plazas as our community and would love to see them into the game.
However it is something that we are still investigating and we can't promise anything right now.
Wow, thank you very very much for this answer!!! :-D [yesnod] Keep on with your great work!!!! [yesnod][yesnod][yesnod]