I've recently had some grief about this feature, or lack thereof. Please vote for this SPR: 617160.
Peter, I currently use that feature with SolidWorks - it's called a custom BOM. I have a BOM called ALL which includes over 30 columns of input. From the BOM you can click on any cell and open the part from there to make your changes, and by having a bom like that allows you to pick up any discrepancies. Also SW does have Assembly Visualization, however I found you could only have like 6 or 7 columns, that works really well if you have only a few custom properties.
Also, if you use Custom Property Tab Builder, you can set it up that you only have a few inputs to make