Awww come on, you've been around! How many X.0 releases have been trouble?
How often have OS-es been shipped with huge problems that take a year to settle down? You really so surprised and feel "betrayed" because 4.0 was buggy and lacked desirable features?
You know, I just don't believe you!
The Developers weren't in the best spot, to take impartial decisions about the software. That was the distro's job,
There were Live CD's to try out, and it was clear many features weren't implemented. Those of whose who repsonded to the pre-release call for wider testing, have said, it was clear to us within an hour or two, that it'd not be ready for general use for a long time.
If KDE had been Fedora's main desktop, they'd have sorted the problems, so someone like Linus could have chosen to install the stable desktop, and play around with the new one when he felt like it.