System Settings is a strange part of Plasma; it composes of umpteen modules gradually written over the last 15 years by a lot of different people.
As each configuration module is generally small and self-contained it doesn't take a lot of continual maintenance so when a developer becomes inactive we tend not to notice.
Unfortunately over time we've seen the number of open tickets on system settings modules increase over time. They get left unsorted as it's "someone elses problem".
This leads to things falling between the cracks, particularly for finding the Plasma 5 / Frameworks regressions as we can't see the real issues through the noise of all the duplicates, outdated bugs and frankly bad ideas.
Whilst I'm doing Plasma this isn't a trend that is going to continue.
I've spent the last week of evenings triaging system settings tickets and fixing up some of the most important bugs.
I need some help on going through the remaining bugs, my personal target is to get the total number of open tickets down to 400 by the end of February.
If you want to help out join us in #kde-quality on Freenode and we can co-ordinate some triage and split out some of fixing, making Plasma a polished experience once again.
A list of bugs split by component can be found here.