A curved phone makes sense now that devices are regularly 6". LG already did it with the G Flex four years ago. It will fit against your face much more comfortably than a flat slab. The downside is that the device's effective thickness will be much greater as you will need to take into account the total depth from the lowest point in the center to the highest points at the tips. For fitting into a back pocket, though, it would be much better.
Not so sure about the hover gestures. Microsoft experimented with it and never got it working acceptably. There is too much variance in how steady a person can hold their hand over a device without touching it, and it adds yet another level of complexity to the system. You'll have tap, double tap, tap and hold, 3D touch, and now hover? Users will be looking like wizards casting a spell if they can even remember what all the shortcuts do.