Spain is at war with Rome or... Greece?
I see that the Mongols can semi-efficiently conquer an enemy if all of the starting Keshiks are thrown at them. On the other hand some civs would not benefit from a war: Greece attacks Egypt? Incas, Aztecs.
The idea is good but should not be a blanket requirement for each civ. I also agree that for any civ that does initiate a war upon spawning, it should be random. If the Goths, Parthians, and Franks conquered (or attempted to conquer) Rome, I'd be happy.
Personally, I'm in favor of allowing civs to be generally feeble (where 2 against 1 usually wipes the '1' off the face of the Earth); and allow these civs to respawn later. Although, while seeing the Persians rebuild their empire time and again, it would be generally biased against humans. Human players don't get a 2nd chance, right?