Well that's the easy part, I got an idea that I would really want to add to the game but I it seems like it would be a beyond complicated code. Basically since the mod starts in 1900, having an empty world is unrealistic. Basically uo have the option to start with a preset world, that is much more realistic than civ. It would place cities, units, routes etc. All before the first turn. But the civs will be on different levels, so there won't be 18 close to equal medium size civs. Most of the civs would be 1 or 2 cities big, realisitcly creating parts like central america, much of Europe. Then several civs would be larger, some over vast areas of desert or tundra (like Russia, Canada, australia), others to represent USA, china, India etc. But those are minor details
Cities placement would be the hardest part, and I would defiantly need help, the rest I could handle with minor help. Something like routes would be on a simple basically get the terrain type and give a percent if there will be a route there. Sane thing with improvements.
Place buildings basically somewhat random, extra chance to get one if bigger population or are a stronger civ.
Place land units based on pop, if Capitol, strength of civ, randomness. Place naval units based on if they have naval buildings.
Place all ancient wonders randomly.
I am sure this is all possible but will take a lot of code. Will something this long crash cIV? Since I'm sure when the game loads it will rake minutes to go through this code. only thing that would be hard is city placement.