I would like an option to show the zone category color in 3D. I am aware that the zone "color" in 3D is currently assigned by materials and that a work-around could be creating materials with the same zone category color. But I think it still would be more useful and quicker to have a way (perhaps something as simple as a "Show Category Color in 3D" checkbox?) to show the same 2D category color in 3D for the same demonstration purposes. Also, if a category and/or color changes, it will automatically correspond in 3D without my having to modify the material as well.
If ArchiCAD is going to persuade users to use the zone tool for building massing, I believe the option to show category color in 3D will be a real handy one.