In a game as Rome, I was surprised to find that Stonehenge was constructed after Taoism had been founded. I just assumed Egypt had spent all that time beforehand working on the Pyramids, but later I received a notice saying the Pyramids had been built - beating Christianity by two turns. You see, here's where we start running into problems. Aside from the currently balanced UHV goals that would have to be revised and the inaccuracy that comes with civs like Babylon being required for the Spiral Minaret, we have trouble trying to apply this rigid form of two wonders per civ to every civilization. Accuracy ultimately suffers to make this rule work, and how unique do the wonders become if we're to balance every combination?