I'd like a procedurally generated Civilization game. I mean:
-The planet's plate tectonics play a part in its geology. For custom worlds, with custom height/elevation maps, there'd be a tool the devs would make in the game to generate a world where your chosen heightmap (for example, a photo of two wooden sailing ships duking it out on the North Sea turned into a square {like 512 by 512 pixels} and edited in World Machine) is shuffled, like how Earth had many super-continents, which then broke off and separated. Basically something to do with tectonic plate movements. You will have to let the tool's seeds take care of it for you, as it'll use voronoi cell patterns, which'll be the tectonic plates. There'll have to be 2 voronoi patterns, because oceanic and continental plates. For reference, a normal world would take a perlin-noise generated terrain from a randomly chosen seed, and use 2 different voronoi outputs for the oceanic and continental plates, which are taken from randomly chosen seeds. The perlin noise heightmap will then be broken apart and reconstructed, as per seed, until separate continents are produced as a result. Your naval battle heightmap will just stand in for the perlin noise. Then there'll be drainage and rainfall maps. Volcanism will happen at fault lines. Temperature will be taken from height. Biomes will be determined by the Whitaker diagram and the drainfall maps.
-All cultures are procedurally/randomly (I dunno which label fits it better) generated. Something like several cultures have randomly chosen preferences, appearances, architecture styles and language. Language will be determined by which sounds and phonotactics are used. That'll come handy when naming cities. Everything else linguistics-wise is not considered.
-Playing stages would have Ancient, Medieval, Classical, and then Modern. Each period would have differing philosophies. Like how in the Modern age, nationalism is more prevalent, thus breaking up empires.