Same thing as it was years ago. Bugs. KDE killed my GMail account and made every piece of mail sort as if it were received on the day I connected KMail when I connected KMail with Google years ago. To this day, a pristine installation of Kubuntu 12.04 will pop up messages somewhere about 6/7th of the top of the screen, while they should be locked to the taskbar.
Plasma continually resetting *everything* which is forgivable where it not for the Notes that I had there - and only there.
Give me seven days of tweaking, and I'll have a broken KDE that's only fixable with a complete reinstall.
KDE is, feature-wise, the pinnacle of a desktop experience today, IMHO. But, it's pathetically broken. And it has been the KDE way from day one, or at least from day-about-ten-years-ago when I started using it.
KDE needs to fix the horribly broken desktop before adding features, simple as that. KDE, as visioned, it not only ready for the desktop, it's a killer desktop. KDE, as functioning, is a broken piece of crap.