some "dependencies" in meta-ebuild IMHO can be unselected from compiling simply using some useflag... although there's gnome-light i think a lot of user would prefer emerge a complete gnome environment omitting only some particular packages (gnome-games or epiphany for example)
the gnome meta ebuild is meant to install _all_ packages that upstream includes in their official list. If you want less, use gnome-light or create your own meta package. We don't have the time to maintain yet another ebuild :) Thanks for your understanding
