Colonel Stapp in the 50's proved sitting backwards was significantly safer and military planes with backward facing seats were initiated by him. Today the military adapts civilian versions for their planes and tend to use forward facing seats.
Many people have told me they would get motion sickness facing backwards.
If you remain upright, the bending moment or leverage on the floor structure will be greater. They would have to make structural changes for the altered crash loading from the seats.
I would be concerned about stuff hitting me in the head also, but presumably they could make safer overhead bins relatively easily.
GBibel
Author
Beyond the Black Box: The Forensics of Airplane Crashes