While this isn't exactly a mod idea, something I'm really desiring as of late is a map that places Civs in the most ideal starting locations for their UAs and/or UI/UBs: Iroquois, Mayans, and Brazil in a huge swath of forest, Inca in a large/wide mountain range with hills galore (preferably without sheep next to the mountains), Songhai with an expansive river for optimal City Connections, Polynesia next to (if not in) a chain of islands that allow perfect Moai placement, Aztecs in a lake-rich region, India in a flood plains region, Shoshone in flat land, and Mongolia and Rome in locations full of horses and iron respectively, etc. And for Civs without terrain/resource dependency would spawn in locations most accurate to their real-life counterpart, such as Egypt next to a massive flood plain river and Indonesia in tropical islands.
This is not just so I'm not resetting a billion times before finally getting a great starting location for a given Civ but so any of the AI also have good start locations. Never feels right when I see an AI Inca having spawned in flatland tundra, or Songhai in an area with little to no rivers, and so on. Like, even if the AI gets insane bonuses at higher difficulty, it'd still be preferable for them to spawn in terrain beneficial to their Civ. Would make winning against them all the more impressive, no?
And with the civs spawning based on "historical terrain", well that's my nitpicky side lol Although Egypt
does benefit from flood plains (being a Civ that leans towards Tall play).
I guess TSL kind of already accomplishes this desire, I know. But with the TSL map I use there are consistent "issues" that make me want to play on a normal map (City-States being a major one), and not all the starts are actually ideal for all Civs. Polynesia, for instance, has to contend with single-tile islands for the most part (and thus no place for the Moai), and Arabia's capital is mainly desert with no rivers; just two or three oasis' for food.
Really bad for the definitive Tradition civ. The map or even map script I'm thinking of would address those issues while retaining the other benefits/flavor of TSL, if that makes sense.