After long consideration, Pat Volkerding has removed GNOME from Slackware.
Pat mentions in the -current ChangeLog that GNOME takes a lot of time to package, so this move should allow more time to be spent on the rest of Slackware.
"Please do not incorrectly interpret any of this as a slight against GNOME itself, which (although it does usually need to be fixed and polished beyond the way it ships from upstream more so than, say, KDE or XFce) is a decent desktop choice."