Their approach to GNOMEisms is to officially support three desktop editions: Cinnamon (based on GNOME 3), MATE (based on GNOME 2), and Xfce (based on more recent Gtk). I don't think they try to tame modern GNOME, and I wouldn't expect them to, since that would be an endlessly difficult moving target.

If you want more detail, you should ask someone who still uses Gtk-based desktops, or try them yourself. I gave up on Gtk a couple years ago.