True, except their making that testing release and calling it "4.0" was false advertising. As such, it's fair to criticize it for not living up to what a 4.0 release is expected to be (it's expected to build on 3.x...).
They should have come up with a new name so that it could be version 1.0. KDE: Awesomeness Edition, version 1.0. Ok I admit my name is lousy, but at least it would have been more honest.
I wouldn't say it was false advertising. If you bothered to read the release announcement you knew full well what was ahead.