I don’t think “copy” could be any simpler; just move (or rotate) an object and tap [ctrl] to apply the movement to a copy.
Although I think there could be be an improvement to the paste function - if there was a key to toggle the location of the pasted object between “paste in place” and attached to the mouse. (after pasted)
If Pasted in Place was used, then I would like to be able to use [shift] to move the pasted object along a constrained line from the ‘in place’ location. (and values could be typed in)
It would also be handy if the pasted object/objects were attached to the mouse by the copied selection’s axis.
It would also be useful if the pasted object was “ghosted” over the current geometry until placed. (So that if you rotate the view, you can still see where the object is attached to the mouse and if “paste in place” was used over a duplicate, you could see it highlighted.)
(I added [ctrl+shift+v] for paste in place too )