Considering the Change Visibility tool, it will be very useful to have some sort of Format Painter. Instead of selecting a set of elements and then using the Change Visibility tool, it would be great to set the parameters you wish to change the visibility of elements to and then click on the elements one by one or as a set by click and dragging your mouse button applying the colour / transparency overrides.
Another useful feature would be to match an already overridden element's 'Change Visibility' attributes and then painting another element with these settings - very much similar to the Smart match and apply attributes tool in MicroStation.