This is just an issue of metapackages. The Debian world (and I believe the RedHat one as well) has collected certain programs that are used together into easy-to-install metapackages. So, the package
gnome is actually a shortcut for installing all sorts of goodies:
aisleriot, alacarte, avahi-daemon, cheese, cups-pk-helper, desktop-base, evolution, evolution-plugins, file-roller, gedit, gedit-plugins, gimp, gnome-applets, gnome-color-manager, gnome-core, gnome-documents, gnome-games, gnome-media, gnome-nettool, gnome-orca, gnome-shell-extensions, gnome-tweak-tool, gstreamer1.0-libav, gstreamer1.0-plugins-ugly, hamster-applet, inkscape, libgtk2-perl, libreoffice-calc, libreoffice-gnome, libreoffice-impress, libreoffice-writer, nautilus-sendto, network-manager-gnome, rhythmbox, rhythmbox-plugin-cdrecorder, rhythmbox-plugins, rygel-playbin, rygel-preferences, rygel-tracker, seahorse, shotwell, simple-scan, sound-juicer, telepathy-gabble, telepathy-rakia, telepathy-salut, tomboy, totem, totem-plugins, tracker-gui, transmission-gtk, vinagre, xdg-user-dirs-gtk, browser-plugin-gnash, gdebi, nautilus-sendto-empathy, telepathy-idle, dia-gnome, gnome-boxes, gnucash, libreoffice-evolution, planner
This is the full Gnome desktop and is not needed to run the Gnome desktop environment. So, while you have
gnome-shell installed, you don't have all the associated applications like games and email client etc that come with the full desktop environment.
This is not a problem and it does not hinder you from using Gnome in any way.
gnome-core is also a meta package, it will install the official "core" modules of the Gnome desktop:
at-spi2-core, baobab, brasero, caribou, caribou-antler, dconf-gsettings-backend, dconf-tools, empathy, eog, evince, evolution-data-server, firefox, or, fonts-cantarell, gconf2, gdm, gkbd-capplet, glib-networking, gnome-backgrounds, gnome-bluetooth, gnome-calculator, gnome-contacts, gnome-control-center, gnome-dictionary, gnome-disk-utility, gnome-font-viewer, gnome-icon-theme, gnome-icon-theme-extras, gnome-icon-theme-symbolic, gnome-keyring, gnome-menus, gnome-online-accounts, gnome-packagekit, gnome-panel, gnome-power-manager, gnome-screensaver, gnome-screenshot, gnome-session, gnome-settings-daemon, gnome-shell, gnome-sushi, gnome-system-log, gnome-system-monitor, gnome-terminal, gnome-themes-standard, gnome-user-guide, gnome-user-share, gsettings-desktop-schemas, gstreamer1.0-plugins-base, gstreamer1.0-plugins-good, gstreamer1.0-pulseaudio, gtk2-engines, gucharmap, gvfs-backends, gvfs-bin, libatk-adaptor, libcanberra-pulse, libcaribou-gtk-module, libcaribou-gtk3-module, libgtk-3-common, libpam-gnome-keyring, metacity, mousetweaks, nautilus, notification-daemon, pulseaudio, sound-theme-freedesktop, tracker-gui, vino, yelp, zenity, network-manager-gnome, gnome,
Note that the
gnome metapackage also installs the
gnome-core metapackage. In any case, the main point here is that metapackages are not needed. You can install each of their component packages manually so lacking one or more metapackages does not imply that anything is actually missing from your system.