Indeed it will be very interesting to see how products evolve over time. Open Food Facts also has a "Food Archeology" project. The idea is to find old products and put them in the database as well. Anyone knows soda cans collectors? :-)

Something very interesting as well is to compare products accross different countries, first to identify differences, and second to see if there is a correlation between those differences and differences in the prevalence of some affections like diabetes or obesity.