Haptics you can feel through a 7mm wetsuit? I'm impressed by that, although I'd not want them turned up that high on my bare wrist! This seems like a winner for vacation diving. For those divers that manage a couple dives a year on the family trip to the Caribbean, you have a device you know extremely well from daily life and that you know you keep charged, rather than a standalone computer you kinda forgot to get se…
GPS doesn't work underwater. Would it be for finding your way back to the boat after resurfacing?
Most professional divers will be using a Surface Marker Buoy which indicates where they are underwater and where the boat should be looking to pick them up.
One feature that would be very useful under water but was disabled was Compass way tracking. Hopefully Apple thinks about it allowing it.