It is against the Arch way when it's not even going to be actively maintained upstream for much longer. GNOME 2's got maybe 6-8 months at most before it's support is gone upstream, and Arch isn't there to act as a "historical archive" of old desktop environments. Especially in the likely event GNOME 2 will stop working right when the inevitable library bumps occur after its support drop. Instead of complaining at the Arch developers for doing their job, you could just switch to Xfce or LXDE if you want a GTK+ 2 based desktop environment. Though I personally think GTK+ 2 is visibly showing its age. I wish there were more Qt-based DE's out there, though I do think KDE is pretty good.
