Great review of the GeoDesign summit, and I can understand how the identity of Geodesign gravitated more towards CAD & GIS Integration and also BIM. Based on the attendees and presenters, that seems to have been the point (or at least the market).
From a GIS professional's point of view, GeoDesign isn't just the marriage of the city and building scales, but it's better thought of as the marriage of geoprocessing and design. As a GIS professional, you set up an iterative design environment complete with land-use type suitability and evaluation models, and you receive feedback on your design as you edit feature classes that represent land uses or buildings. The intent for a GIS professional would be to maintain this iterative design environment and allow non-GIS pro's the chance to design and receive statistical feedback on their designs. The point is that many stakeholders have the chance to design and review other stakeholders designs. You can measure agreement and disagreement spatially.