Next gen or future Duo probably wouldn’t be able to fit Face ID too. The TrueDepth array sensors are really too thick to fit into the 5.2mm (when unfolded) chassis of Duo liao. I believe the threshold to fit the TrueDepth sensors is 5.6mm and that is the current thickness of iPhone’s slimmest slab phone - the iPhone Air.
Actually I’m ok with Touch ID too, on the Duo. It’s fast, fool proof. I’ve been using my ZF8U for a month+ now and I’ve gotten use to it. I’ve set fingerprint, and face recognition on it. But highly secured apps like iBanking still requires your fingerprint authentication. The face recognition bit on Samsung can only unlock phone, and I must say it’s as fast as FaceID on iOS too.
FaceID sometimes on my car MagSafe holder, I got to shift or tilt my face abit to face my phone when I wanna read WA msgs at Red lights. TouchID no need, one hand on steering, another hand can unlock phone, eyes fully still concentrating on road.
The only bummer on Duo, for me, is the usage of the nano-texture material for the inner screen. The Super-Retina OLED really can’t shine out the vibrancy. I’ve seen the MacBook Pros at Apple Stores with that nano-texture matt material and I really dislike it. The colors just don’t pop. I’ve never seen any high end Samsung or LG TVs using matt screen to hide their micro RGB vibrant Oled.