Looking good Effendy! Those buildings are perfect! Low poly too!
Be careful of using SUPER MOUNTAINS.... perhaps make one or 2 sides of the horizon more interesting, as its quite non logical to have city within a center of the mountain...
For that big building on your last post.... maybe you can consider using UNREACHABLE areas, so that the player can see the building, but not necessarily be able to go So close to the building....
So Perhaps make it like a city GATE... and beyond the gates, is this government building, which you cant enter..
Keep up the good work!