Okay, my first map is finished. This is my first attempt at making a map for a modded Civ5, so if you encounter any bugs or weirdness, please feel free to contact me so I can try to fix it. (And maybe tell me how if I don't know how to fix it myself.)
The map "AD v18 Random 12+24" is designed for the base mod of Anno Domini (v18), so no additional civ packs were loaded while creating it. I just tested it briefly with the base mod as the only mod enabled, and everything seems to be working as intended: Start locations are fixed but randomized (if that makes sense ... there are 12 "Random Player" starting locations and 24 "Random City State" starting locations). I suppose other civ packs can be loaded with it. Not sure how the game will behave if you try to load more than 12 major civs and 24 City States, though.
Now, briefly about the map - I designed it specifically with 12 civs and 24 city states in mind, so the resources are all balanced around that. I tried to keep strategic and especially luxury resources sparse, so there's a total of 10 instances of each luxury (for 12 players), and Iron/Copper/Horses aren't abundant either. Each starting location has been provided with the same amount of resources, but the resources differ - 4 have Iron, 4 have Copper, 4 have Horses, and of the "minor" strategic resources (Barley, Pigs, Stone, Limestone), each civ has 2 Stone and 4 instances of one of the other three. City States have less but each of them is of equal worth resource-wise. And then there's resources scattered across the free part of the map, of course. The only thing that's really abundant, though, is fish, because I got too lazy to count (all other bonus resources have 60 instances each on a Huge map). Also, every single Natural Wonder is present on the map. I tried to distribute them evenly, and the "special" ones (Hippocrene, Mount Ag...something (the one that gives a promotion), Midas' Palace, and Valhalla) are each in special/"secret" locations.
So ... let me know what you think if you want to test it! (The map itself does not try to imitate any real place, soooo it's just like playing a randomized game except I've put a little more thought into the map than the algorithm does.)
I'm going to expand this map into an actual scenario where I'll place cities and stuff. That's what I've wanted to do ever since I discovered AD, but up until this version I could never launch the World Builder with the mod (or even without it; reinstalled it and now it's working) so .... yeah. [EDIT: Or not. This is a buttload of work, and I'd have to do it all over again for the next version if I place units and buildings specific to a certain civ.]
Edit: Okay, not all is working as intended. Player 1 always ends up in the same starting location, regardless of the civ. Probably the first one I picked but possibly also the one the game thinks best. It's a Flood Plain start, so if you want to try the map as it is, pick a civ that fits the terrain ... until I find a fix (or someone tells me one).