Both arguments have merit. However, trying to simultaneously support both approaches in a library would be a nightmare with the program’s current user interface.
So if I turn the nightmare into a dream, I may as well dream in vivid colors. How about . . . the ability (in EESchema) to place ALL the sections of a multi-part symbol at once. Yeah, both halves of the DPDT switch, or all four gates of the SN7400, or both amplifiers of an LM358, etc, all parked on the schematic with one mouse click. You could use them as they land on the page, move them around as a group, etc. Or . . . . with another mouse click (perhaps an addition to the “Properties” menu invoked by the “E” hotkey) you could treat each unit as an individual part - essentially the way it works now. Name the option “Uncouple”, or “Separate”, or “Explode”, or some other name you like.
Dale