People probably will need a GUI. Imagine playing this game without the Board diagram, and trying to figure out how to navigate from point A to point B. All the information would be there, but there would be no visual diagram displaying the important stuff in a friendly format.
Not only would 3D be enormously difficult to navigate without a GUI, it will probably even be difficult with whatever GUI I can write, given the 2D nature of a web page and my limited experience with 3D graphics. Things would probably be better if the world was just in 2D (keeping everything else about the idea the same).