Is there any way to set a default action for drag and drop in dolphin, like move when the source and target are on the same disk, and copy otherwise? Most file managers do it this way. I also find it strange to offer MOVE as the top option when drag and dropping to *removable* media.

My dream default action is to move when staying on the same disk, copy otherwise, and to show the menu when drag and dropping using the right mouse button. Any way to fulfill my compu-utopian fantasies?

Hilarious: I found my own post on this (I forgot about it) a couple of years ago, except that I now have a better idea of how the default behavior should work!

viewtopic.php?f=22&t=92785

This question has been asked before. The behaviour you are describing as "desired" is that followed by Windows I believe.
At this time, no option exists to configure KDE to provide such behaviour.