I don't know what you guys think, but I think this needs to be revamped a little. I think it works better as a small wonder, because then you really get a better picture of how the world encountered nuclear weapons.
Basically, each nation had its own bomb project, and these were completed at seperate times (China's was well after the US and Soviets). In between there was a period where one could hold a very strong amount of bargaining power over another (that was one of the main reasons for bombing Hiroshima, to show the Russians what they were capable of). It doesn't really unbalance the game or anything, indeed I think it's more balanced since you can give the potential for nuclear weapons to civs way more powerful than you with the current model.
Basically, each nation had its own bomb project, and these were completed at seperate times (China's was well after the US and Soviets). In between there was a period where one could hold a very strong amount of bargaining power over another (that was one of the main reasons for bombing Hiroshima, to show the Russians what they were capable of). It doesn't really unbalance the game or anything, indeed I think it's more balanced since you can give the potential for nuclear weapons to civs way more powerful than you with the current model.