@makeixo I'm curious what gestures SFOS uses? As I see it there is really only 3 easy gestures per edge: quick flick, and long drag (perpendicular to edge), and sliding along the edge (parallel to edge). Currently only the indicator edge implements a parallel action.
I missed the 'back' button when I moved from Android, but these days I find it awkward when I use an Android device that the back button does inconsistent things... sometimes it move back in an app, sometimes it closes an app, sometimes it switches apps. My point would be that I like how UT has separated the concerns the 'back' button provides. App switching is on an edge, and induvidual apps are left to determine where and what a back functionality does (many don't even need it).
A global back gesture would have the same problem, what back action should be implemented in a given situation? Is this up to Unity8 or the app in question? If it is on the app, what happens if the app doesn't implement an action?
Thinking further about my example of Morph, the 2 basic gestures on the bottom edge would work, and could be just like the new app drawer coming in the next OTA; a short flick could show the address bar and a long drag could switch to the tab view. And all functionality would be maintaned with an easier to reach 'back' action.
If I was able to (and who knows, I might learn) I would add a parallel action to the right edge, so that sliding a finger up and down the edge would simulate a scroll wheel.