TL;DR
The copy&paste shortcuts should allow toggling the options to include entities, tiles, trains and station names.What ?
When making a blueprint one can enable or disable entities, tiles, trains and station names. This should also be possible with the copy&paste shortcuts.The way I imagine this is that one takes a temp blueprint using ctrl-x or ctrl-c as before. Then when the blueprint is shown 4 buttons appear somewhere ad the edge of the screen for the 4 blueprint toggles: entities, tiles, trains and station names. The blueprint would include everything but the 4 buttons dictate what is shown and pasted when placed.
Note: This could apply to any blueprint with those options not present in the blueprint disabled in the GUI.
Why ?
When I'm playing with the SeaBlock mod anything new to build first requires landfill to be placed. That means any blueprint should have tiles included so it can be shift-placed to add ghosted landfill first and then later placed again to actually build the stuff. This often means the copy&paste shortcut can't be used.When playing with the Logistic Train Network mod having stations with the same name other than Depots is an error and deactivates the stations with the duplicate name. That means after a cut&paste both the original and new stations stop working till one goes around and renames on of each. In that case it would be nicer to create new names for every pasted station like a blueprint does when station names are disabled.
Note: Even better would be something to add/increment a number to each station name. So when I copy&paste "Smelter" it becomes "Smelter 2", copy it again and it becomes "Smelter 3" and so on.
Again when playing with LTN when I copy&paste a depot it would be nice to optionally include the trains.
When I build a road network for faster travel (e.g. stone paths) then it would be nice to copy&paste just the road. Ignoring all the buildings around the road.
Overall I can think of examples for any of the blueprint toggles to apply to a copy&paste job.