Libglade consists of more than one library. One is called libglade.so.0 and is not gnome-dependant. Another is libglade-gnome.so.0 and depends on gnome-libs et. al. This makes the whole package depend on gnome-libs. Although it will work to install the package with --nodeps and use libglade.so.0, this is not a good solution. Other distributions have split this package, so as to not require gnome-libs to use libglade for a gtk+ only application.
In GNOME 2 library packages (alpha versions at ftp://people.redhat.com/hp/gnomehide), libglade is already split in this way, I don't think it's worth doing for libglade stable. We require gnome-libs for the base install with X anyway, pretty much.