I'd like to see a whole mathematics tech tree. Also I'd like to see each culture that invents a numerical system getting a random (or less random) value assigned to the efficiency of their system. The Arabic numerical system was so much better than the roman counting system that it allowed them to progress in mathematics much faster, to the point that pretty much the entire world ended up adopting their system. Also the concept of Zero should not be taken for granted, it was actually a rather important discovery.