Players appear to not be aware of the feature to download and fight against other player's cities online, which is one of the biggest features in the game and have contributed to comments there isn't enough to do. Previously this mission would unlock after your own city would be attacked by the AI.. I've decided to move this feature to the beginning of the game, to NPC cities.
These cities are only added for new games and spawn near the edges of the map. They don't yet offer quests, because I can't add dialogue while the Chinese localization is still in progress for the next two weeks. Comment in the thread City mission design if you would like to offer feedback on what quests should be offered.