As above...
Camera: I guess the super-wide camera comes down to what you will use. LiDAR was talked about on the presentation. It'll be very useful for measuring and augmented reality, but also assists the cameras in low light situations. In dark scenes, it will allow for more accurate focusing in portrait mode, as well as quicker autofocus. There is also the higher optical zoom that is possible too. This is the main area of change.
Double the base storage.
It's made from stainless steel and not aluminium, so will feel nicer, be heavier and look more premium.
Extra 2GB RAM in there too.
However, the 12 and 12 Pro are identically sized, using the same screen, speakers, battery, A14 chip...