1. The 4GB limit on point clouds is not sufficient for modern hi-res scans of large objects (like buildings)
2. More formats supported. Personally I'd like to see import support for RCS, RCP, LAS and LAZ, but there are other popular formats too. Every time a big point cloud needs to be indexed/reformatted, it can mean half a day of lost productivity.
3. Point clouds should have an independent "lock" or "freeze" feature, that prevents selection of the point cloud while working in 2D and 3D views. With millions of points on screen, it is a challenge not to select the point cloud itself (even when the layer is locked).
4. There should be an independent "view range slider" in floor plan views that affects only the point cloud and not the Archicad model. It would be nice if this was relative to the Story Elevation and Height to Next. This should function even when the point cloud or it's layer is locked.
5. Colour point cloud filters are very helpful when dealing with non-RGB scan data. Many other packages provide colourization options. The most useful tend to be elevation and normals filters.
In my opinion, Graphisoft should have a look at Undet - they seem to be ahead of the curve for point cloud visualization in non-native software packages. Their plugin for Sketchup is fantastic. In fact, Nemetschek should just purchase Undet and incorporate advanced point cloud support into their entire product line.