this is one of the projects i've seen at cebit. it's not really new but still could be an interesting way to discuss a project inside an office or with clients. still in the current implementation i see two main problems.
first it should be able to generate the necessary sections and plans from a model made with for example autodesk revit. all the necessary informations are already included in such a model and the extra step of programing the interactions just doesn't fit to make quick modifications to the model.
the second issue is related to the camera navigation. in my eyes it's extremely important to give the viewer also the possibility to look up and down and not just to rotate horizontally. this could maybe be done with another technology i've seen at the fair. this technology adds the possibility of measuring not only 2 coordinates of a finger but also the distance to the screen making a third dimension of input possible. that's just an idea but we will see what future brings.