In google sketchup, you can draw a square and extrude it anywhere on a mesh as long as it’s flat. In blender, if you have a face which is extruded and scaled down, and extruded again, you have a hat shape with trapezoids composing its base. In order to make a square hole there, you have to delete most of the base and fill it with shift f after adding a square there. This is quite tedious. And I don’t use the KMZ export script because it is unreliable and rarely does it right. It leaves holes in random places and with a big model, I hate to fill them all up. Also extremely useful would be the offset tool. The offset tool in sketchup shrinks a flat face in a way I haven’t found how to do for blender, the result being a shape with an equal distance from all the faces of the original polygon, leaving a nice even margin to extrude or color or whatever. The follow me tool could also be really useful, because although bevel objects on curves could be argued to be enough, if you try to make them go vertically at any point, they twist, and curve tilt can’t fix this no matter how I twist it. And just as an in-editmode modelling tool, it would really be usefull for pipes and drains. The three-point click technique of making a curve from one point to another and even all the snapping in sketchup would make architecture easier.