obfuscated code with a lot of short cuts is likely also not the best way to model the world :P but this is definitely an impressive feat :D i'd be happy to get it done in like 256 lines of code, likely it would take much more than that! XD...
as for visual stuff. a lot of things man made and natural follow patterns (otherwise it'd be hard to recognize anything). So there's a lot of maths stuff you can use. Different types of noise or other patterns line for the height textures, fractals can be used interestingly, fibbonach/phi ratio for vegetation/trees, size ratio between skeletal elements / bones etc. - don't need any magic guessing machines for any of that.