[md8z]

"They're not supposed to be tightly integrated, the gnome team seems to have forgotten all of this."

That is a misconception that I've noticed, maybe it's because KDE uses different APIs for a lot of things, or maybe it's because of the way some distributions package it. But none of the Linux desktops are really that tightly coupled when you actually dig into it. For example managing the desktop settings is handled by its own daemon appropriately called "gnome-settings-daemon" that loads all its settings modules via a plugin system. KDE is structured similarly in that its code is split across a great number of small support libraries. If there is no secondary consumer of those APIs it's probably because nobody has bothered yet to make and test additional combinations of packages that actually work.