The default Screen Saver preferences window in Ubuntu has almost no options available. One can choose the screensaver to use, but can make no customizations at all for that screen.

For some screensavers, this is minor, because it might just be to choose the number of objects on screen, or the speed of the screensaver. However, with some screensavers, slideshow ones in particular (eg GLSlideshow) having access to customizations is essential. Most critically the user needs to be able tell the screensaver the location of the images to be shown. Additionally the user might want to adjust the other parameters. GLSlideshow, for example, has quite a few parameters available, but they cannot be accessed with gnome-screensaver. Some people manually search and edit the config files - this is what keeps Ubuntu as a geeky OS rather than a sleek OS for human beings. I found that installing the Xscreensaver 5.04 package allowed me access to most of the parameters. Xscreensaver is not perfect, but it is much better than gnome-screensaver. If the latter does not improve, it should not remain as the default screensaver package.

Regarding Launchpad bug is https://bugs.launchpad.net/ubuntu/+source/gnome-screensaver/+bug/226377