So many options placed seemingly at random. Similar options like lockscreen, login screen and desktop background settings spread out over 3 different main categories.
Customization options so extensive and granular one can only wonder about their purpose. Even in their latest release blog post they chose to brag about the new ability to change intensity/thickness of frames. I don't think most people care about stuff like this.
Until recently defaults were straight up insane like single click to open folders/launch programs, touchpad scroll being inverted etc.
If you navigate to Settings -> Sound you'll be presented with some options but also buttons in the top right that will open a mostly empty screen with a few additional options. Why not split the whole page into parts and present everything on a single screen? Why not tabs?
Sometimes those buttons in the top right have different behavior. Some will open a whole new page ansd sometimes it's just a popup and other times it's a dropdown.
And oh man just navigating Settings sucks. Main list consists of single and two level options with two level options opening another, mostly empty vertical pane so the actual size of the right pane changes with top text jumping around depending on what you press. So why some settings have two levels and some have tabs and some have those junky top right buttons that need their own back button to show up in the interface whenever they're pressed? I'm not for or against any of those design choices but why all of them at random? I just want some goddamn consistency.
Cherry on top is the bloat most distros choose to install alongside Plasma desktop. Dragon Player? kMail? Does anyone even use these? I dislike Gnome a lot but at least their preinstalled software is minimal, elegant and actively supported/developed. Most KDE programs look like they stopped receiving updates in 2008.
I still think it's a great DE but there's much room for improvement.
GNOME and KDE sit on extreme opposite ends of the minimalist/maximalist spectrum.
I remember spending hours customising the KDE 5 task bar clock, trying to correct the padding. Eventually I gave up customising it and switched to GNOME.
KDE app customisation is also a mess compared to something like foobar2000.
I think emacs does a very good job at this. You can configure most of the settings people need to be productive in a text editor from the menu bar while leaving the extremely rich customization of emacs to the options menu and elisp config files