All the same terrains = boring and lazy
If anyone else was incredibly bored with the Empire factions all being stupidly Death Blasted Land (despite contrary faction descriptions) and the Kingdoms all being Goodly Grass Land, this changes it to give the factions more varied terrain, it changes absolutely nothing but terrain and color schemes so it's completely patch compatible and will only ever interfere with a patch that diversifies their currently boring homogeneous terrain types (and slightly colors).
Hopefully Stardock will officially do this at some point. It really makes no sense that some of the factions would even have the terrains they have given where they're supposed to be located. It would be tempting to come up with some ad hoc excuse for why the empires all have the same terrain, but it wouldn't make the game any more interesting or aesthetically pleasing.