Eddiit, yes I remember your name and your avatar! You were one of the first here but later you faded away. Anyway, the current "fall" system isn't, as it was at first, a semirandom event. At first some civs had bigger chance than others to be converted to barbarian cities, depending on random variables. (thus, semi-random). Then, having introduced strong barbarians, I've dropped this system and introduced 2 collapse conditions: 1-if in a few turns 1/3 of a civ's cities are controlled by barbarians, the rest falls. 2-if the number of cities is less than half of the number they were some turns earlier (so, conquered by any other player), the civ collapses. Though quite realistic, I know it might seem odd to see an enemy fall right when fighting it, but for both loading times and for helping new civs to grow stronger, some civs have to fall. With Warlords, and a higher number of teams, this need will be even more important. If you have a better idea on how to make it more realistic, I'm all ears. But some civs MUST fall.