I sincerely hope you're griping about the fact that Fedora forced its users to switch to KDE 4.0, which KDE strongly discouraged distros from switching to in the first place. If you think of it as an open-source tech demo, you're close to the purpose. A complete rewrite takes time, and KDE is all about openness. So, while they were busy working on a newer, more flexible version, they allowed people to try it themselves. The upcoming 4.2 release is extremely usable. I'm thrilled that I can boot up my desktop, and wow my non-Linux-using friends with it.
So my point is this. Fedora screwed up here, not KDE. KDE followed its principles, and has maintained the entire time that what they were working on was not "ready for production use."