I don't know how hard it is to implement, but will there be a conditional Eastern Roman spawn in the 3000 B.C. scenario? It should definitely only be if Greece is gone and it is controlled by independents/barbarians/Romans.
One problem with the spawn in general is that Egypt doesn't flip to Eastern Rome either, which is weird if Western Rome controls Egypt, thus resulting in it having distinctly eastern holdings. I'm fine if Egypt is controlled by barbarians/independents or even Egyptians since Eastern Rome can easily take it then, what with Egypt probably being way behind on tech at that stage.
Also, it's weird that Eastern Rome is ahead on technology compared to Western Rome. I don't know how you would fix that, but it doesn't make any sense historically.
Also, and I'm not 100% sure on this, but it seems to me that Western Rome takes a hit to stability if it's losing cities to Eastern Rome. If anything it should be the opposite.
Now, the big problem with an AI Eastern Rome spawning is that it conflicts with the 476 deadline for controlling Greece and Egypt. You could just move the deadline to just before 330 for only Greece and Egypt, though that almost qualifies as a 4th UHV condition.
Minor point: you should change the names for Rome and Byzantium to Western Rome and Eastern Rome when both are alive.
Finally, I must say that playing as Rome it's kind of weird to watch your territories sucked up by France, Spain, and Britain, when nothing of the kind happened historically. Plus, by the time they DO spawn you've probably gotten the barbarian situation under control so maybe they should win a bit before Spain spawns? That may or may not counterbalance an earlier deadline for the territory gains.
Whatever you do, keep up the good work Leoreth, this is a great modmod.
