Kubuntu is the most likely KDE-based distro to be adopted in a business environment due to its Ubuntu roots (businesses want to reduce risk compared to a known quantity). Accordingly, we should audit the default visual presentation to make sure it's as professional as possible.
One thing that I think has to go is the default setting of making windows translucent when moving or resizing them. This effect seems really gimmicky and unprofessional, and no other major operating system implements it. It's pure eye candy, but it's not even particularly useful eye candy since the translucency obscures the window's contents as you're resizing it.
GUI-wise, this setting is in System Settings > Desktop Behavior > Desktop Effects > Translucency. It defaults to on; we should turn it off.
(Upstream task to make this this default is tracked in https://phabricator.kde.org/T7682)