Pie provided me with an initial dll wishlist:
-) new Mission: drive out religion
Missionaries can remove religions from a city. Up to now, that's a special unit in PAE, that should be merged with the normal missionary.
kmod implements some chance, that failing missionaries can remove another religion from the city. That should be disabled.
-) Ramks Rivers
That should be implemented by Ramk
-) Generals should only defend, if they are the most healthy (not only strongest) unit in the stack (lead from behind, if you will)
-) Population numbers. Such that Pop 5 doesn't mean 500'000 people in a city. Pop 1 around 500 people, Pop 6 around 50.000. Pop 25 close to 1 M.
Previously: Pop^2.8 *1000.
Suggestion: round(Pop^2.8) * 100 + 400 yields Pop1: 500, Pop6: 15500, Pop25: 821200.
Alternative: round(Pop^2.09)* 1200 - 700 yields Pop1:500, Pop6: 49700, Pop25: 1001300.
For the first version I'll put up a PR. I like the slower start with 500, 1100, 2600, 5300, 9500, 15500 vs. 500, 4100, 11300, 20900, 34100, 49700.
-) Forts in enemy territory: defensive bonus for whomever is occupying it. Currently, PAE modifies the plot culture to change the ownership accordingly.
-) Forts and lookout towers with +1 vision range for units on them. Currently, a promotion is given dynamically onUnitMove.
-) Ice on water: should be accessible to land units and not for ships (except for submarines, which PAE does not have).
Something like a "FeatureMakesValid" tag for movement?
-) Terrain: Desert, swamp and tundra should cause damage. Low priority feature. Already implemented in the old project and could be merged.
-) UnitClassType: Chariot: should not be able to move through the woods (forest, dense, jungle; but savanna is ok). Any road enables movement. Optionally the same for heavy siege weapons.
How could the AI cope with such a rule? Path finding is so far no part of their production planning, I guess.
-) Unit religion: each unit is assigned (statically) a religion based on the city where they were recruited. If two units meet on the battlefield who share the same religion, it might happen that they refuse to fight each other, or one side might defect.
As written before, that's also at least partly implemented in the old project