In SU, the Copy command is invoked as a sub-species of the Move Command, by using a modifier key. The process is to select the object, select Move, hold down modifier key, place the copied item. Then the command default reverts to Move. You have to hit the modifier key for every fresh copy. Might it be better if copy command was retained as default until, say, you hit Esc or the modifier key again? That would mean you could make multiple random copies without having to hit the modifier key each time.
I realize that you can use multiply and divide to create arrays but that is no good if you wanted to, say, populate an elevation with copies of a window that are not regularly disposed. Or if you wanted to create a random population of trees on a site plan.