^ How? I imagine you have to do something which is either difficult or not very obvious, especially to new users.
I would like to able to configure them through the screen saver selection utility, definitely. If for nothing else, there should be the option of selecting which folder(s) to include in the slide show screen saver, rather than having to use your default pictures folder.
You can configure screensavers, just not through gnome-screensaver, which is the default application. And that shouldn't be the default, it shouldn't even be considered ready for release without being configurable. And since the author staunchly refuses to add configuration options and nobody's made a fork of it, we ought to go back to xscreensaver. That program has options that Just Work.