Heavenfall, if you have time, I wonder if you could do me a favor. Try modding the TerrainTypes.xml file by setting the MaxHeight tag in the 'City' terrain type to 1000. When you build your first city, the city tile will suddenly form into a huge spire! That is if the mod is working. That's what happens when I mod directly to the install directories.
The reason I'm trying to figure these values out, is because I am now making very nice and functional multi-level high relief maps... but there's a snag. When you build a city on a higher altitude than normal, the tile will morph to the height value contained in this variable, which is normally 50. That basically causes the mountain you are on to melt away. It's all super annoying.
There is a MaxHeight and a MinHeight variable, but the cities seems to morph to whichever of these is highest. I'm thinking its a bug that they didn't notice because normally they both have the same value of 50. I'm hoping I can find a setting that will trick the game into leaving the altitude alone.