I agree. KDE 4.0.0 is a huge disappointment.
If major features are not available in SVN/CVS or an alpha release or maybe even a beta release, that is understandable. However, releasing KDE 4.0.0 prematurely was a mistake. Not only are many things missing (there's not even a kmail!), but some
packages don't even build correctly (kdegames, kdebase-workspace [ksysguard], and kdeedu [kletters, kalgebra, a couple of others]) due to XLM errors in documentation files.
I do hope that the configurability is restored, but there is no way this release should have been called a final 4.0.0 release until then.
I do fear there are some changes which will not be fixed, though.
For example, 'systemsettings' seems to have completely replaced kcontrol. Even if all of the configurable modules from kcontrol are added to systemsettings, the interface to systemsettings is much less usable than that of kcontrol.
I can't find any way at all to configure the panel, add applets, etc.
The ability in plasma to add new widgets that show up on the desktop is all but useless for those of us who actually like to use most of our screen space for program windows.