I believe it's a lack of good / opinionated defaults. KDE is deeply customizable, and once you have spent some time tweaking it you can have a great looking des

I believe it's a lack of good / opinionated defaults. KDE is deeply customizable, and once you have spent some time tweaking it you can have a great looking desktop. However, most/all of the distros ship with a bland/conservative default, which is probably supposed to be generally appealing, but in reality is bland. They badly need a design lead who can overrule the status quo.