I would like to suggest the live display of CGs and moments as items are repositioned in a drawing. As a drawing grows and becomes more complex, it might be useful to have an ability to know if the CGs and moments sums change the model balance to something unacceptable. A condition of Unacceptabilty could defined as user-specified distances along the x, y, and z that should not carry x% more load than some weighted average in a region being looked at.

So, if 5,000,000 kgs of mass is to be distributed along 170 m of length, 20 meters of breadth, and say 30 meters of height, the user could divide that mass equally across some number of sections of the length. Some sort of stress or bending moments curves could show deflection lines, graph bars, or colored spheres or something (not to be an engineering program) to simplistically show the use that his/her dragging and dropping of mass is not some even distribution.

I might have suggested it before, or it might be one of those 51 or 52 suggestions I've not posted.