You don't need any "hack", right in System > Gestures > Navigation, all three options are openly available (100% gesture, 2-button + gesture, old 3-button style

You don't need any "hack", right in System > Gestures > Navigation, all three options are openly available (100% gesture, 2-button + gesture, old 3-button style). I believe they intent on keeping it all available for sometime, if only for accessibility reasons. Also, the charts show that it's either equal and better, and there's also the implicit fact that not showing buttons also means more screen space, so even if usability metric is the same, visually it's a win.