In no particular order.
1. The project pane filter is good. I would like to see it expanded over folders. That is, filter (show) all the drawings or tables that are within a folder tree (or a selected folder tree).
2. Allow the user to set the project pane default position as floating and not linked to the right side of the screen.
3. Autohide the project and the contents pane while these are floating or linked over the main screen. Manifold 8 creates these nice tabs for various panes on the side of the program that permit more screen real estate. I'm sure this (or something like it) is probably in the works.
4. A freefrom drawing tool . Lately Ive been digitizing using 8 and find that the freeform style tool for digitizing lines is very usefull for coastal and vegetation drawing.
There are some others.