I've talked about this before, but i'm gonna go ahead and make an actual list to keep track.
With all the changes to the mod, Persia is perhaps the most overlooked civilization and has a very unfair starting situation depending on how advanced Babylon is. So here are my suggestions to make Persia more fair to play:
1. Nerfhammer Babylon.
Many of us have mentioned it, but Babylon just loves to beeline certain techs, and frighteningly it often goes straight for Feudalism and has longbows by the time Persia spawns. Not only is this unfair in terms of combat, but no civilization should be in the middle ages by 800 BC (unless you're Youtien). So here are a few options for nerfing Babylon:
A. Make the copper NE of Babylon only spawn after the Persian spawn. This way Babylon can still get to bronze working, but it may not have enough time to raise a force of axemen and spearmen to counter Persia and will have to rely on their UU instead.
B. Make Feudalism require more techs, or change Babylon's teching priorities. Feudalism is definitely too easy to reach if the AI does it the majority of the time. I think Calendar and maybe one other tech added as pre-reqs would be a good way to slow Babylon's advance a little.
C. Remove either the stone or marble near Babylon depending on what wonders they need to build. Babylon is pretty productive, maybe too much, and that's perhaps part of the reason they can outlast Persia since they can quickly produce an army if they so wish. And they always build the Oracle before Greece can, so it would help the Greek UHV as well.
2. Give Persia more settlers at spawn.
Now with the core/periphery rules in place, Persia has to focus on filling their core to avoid stability issues from trying to reach 8% territory (and mind you, Iran has little food). They have four archers but only one settler to found Parsa, so they could probably use one or two more to help fill out the rest of Iran.
3. Push back the spawn date for barbarians.
I've seen Parthian horse archers spawn as early as 3 turns after the Persian spawn. Sure, they usually go after India instead, but having barbs spawn that early when you're more likely focused on conquering Babylon is kind of unfair. I think Persia should only be experiencing barbs after the Greek conquerors spawn, as before that point Persia was pretty unified. Correct me if I'm wrong on barbarian pressure on Persia.
Comments/additions welcome.