noticed an issue, not sure if this was intentional or not.
civil engineering states that you've removed urban defenses. looking through here, the only mention of urban defenses being removed was where you mentioned that the bastion policy was meant to be a replacement for urban defenses (and indeed, in the code, you even referred to it as "quo_bastion_urban_defenses"). However, upon researching civil engineering, bastion becomes obsolete. I'm guessing you added bastion before you removed the urban defenses, and made it go obsolete because bastion+urban defenses is redundant, but when you removed the urban defenses, you forgot to stop bastion from becoming obsolete.
personally, I prefer having bastion available, and then becoming obsolete once urban defenses become available. While urban defenses make your defenses strong, they also make the AI's strong, and although the siege can now shoot from safely outside the town's range and only needs -someone- to see the city, this means putting that someone within range of the city, both to defend your siege from troops sallying forth and to give vision to your siege, and even then, without battering rams (which are obsolete by this point), 200 fortification points are a lot to go through.
that said, your code is simple enough that even if you and most others disagree with my view, I can edit it anyway lol
also, due to using omnibus and this mod in tangent, I found another bit you might've overlooked. Scouts get an extra level upon creation, but rangers do not. If you start a game in the modern era, your rangers will be level 0 (or, 1, whatever, 0 promotions), and if you find any goodie huts late game and they decide to scorn you by giving you your 17th recon unit, which will now be a ranger, it will again have no free levels. you can fix that by just adding a bit of code at the end of the recon line to read "UPDATE Units SET InitialLevel='2' WHERE (UnitType = "UNIT_SCOUT") OR (UnitType = "UNIT_RANGER");"
something else I noticed is that stonehenge, for some strange reason, builds really, really fast. I noticed this when your mod was the only new mod I added, so I can confirm it's the tweaks in particular. I've been playing on marathon and found that, while similar buildings are taking almost 40 turns to build, stonehenge is only taking 5 turns. while it looks to be intentional from the code, I'm surprised no one's brought it up in this forum yet. why is stonehenge so fast?