I'd love to see to customize any folder or note to specify what columns would be displayed when that folder or note has the focus in the left-hand pane. So when I put the focus on the folder for students in my current class, the overhead display would include a column with their grade. When I clicked on a folder with my task list, the columns would show due date and a done column. A folder full of contacts might show addresses and phone numbers in the columns. Etc.
I don't use the custom columns much at all, because unless I'm mistaken (which I may well be) they need to be set up for the database as a whole, and the columns I want to see are all context dependent.
This would be a killer feature, equal in importance to the fact that Mori blurs the distinction between notes and containers (the only other application I know that does the same is tinderbox, which doesn't seem to have a table oriented view at all).