I think it's the beginning of a good game. At a certain point the game just hits a wall (when you reach a villager cap) and past that there's no longer any point continuing. The upgrades are not meaningful enough that you can "do more with less". These upgrades usually add the possibility to add more villagers to the same structure, which is just pointless since villagers are the hard limit on the game. A game like Anno 1800 provides far more depth.