Face ID is very good but I think touch ID also has it's advantages. I honestly think touch ID under the display would really make the next iPhone much more happier to use. Face ID is more convenient while downloading apps or logging into my bank app and others. While touch ID would be better when unlocking the phone since it's kinda annoying having to pull away the iPhone X while laying down in bed just so my face can fit in the view better. Also having it at an angle. It's great but I don't think it would be ready to replace touch ID yet and also another thing. IF Apple was able to use touch ID under the display they would of avoided the notch by placing the selfie cam and speakers in the ridge at the top of the iPhone by simply making the camera lens smaller but wider. But Face ID requires a lot of modules.