I would like to see some dynamics in the game that encourages you to want to stay small. I am getting sick of the bigger is always better concept. The maintanence setup is good, but I am after more bonuses/benefits that would be lost if you were to expand. Here are some ideas:
*a uniqueness bonus. The greater the Wonder to the number of cities ratio, the more unique your empire is. This will inturn give you massive bonuses to growth, productivity, commerce, diplomatic relationships, etc. Greater xp for units built (higher morale). Increased trade and increased number of trade routes. Faster wonder construction for cities that already have wonders. Automatic Open Borders with all civs (for better or for worse). Population boom. Etc. All of these bonuses diminish or disapear as the Wonder to number of cities ratio gets smaller. A large empire will never be able to get these bonuses.
*a small empire that proves its leadership skills will be entrusted with another leaders decision making so that you will control their empire. Make decisions that result in your gain and their loss and you will loose that priviledge. The smaller the power rating over your entrusted leader, the better. If you start to grow in power faster than they do, then it signifies that you are getting more out of the deal (by taking tech and not sharing it, similar with gold and resources, etc). This can happen to multiple leaders so that it effectively creates a massive diplomatic empire that can fall apart if the power that is given to you is abused. The smaller your empire here, the better. A large empire will not be able to achieve this.
*have other bonuses that can ONLY be gained by being small. Expand and those bonuses diminish or disapear all together.
*a uniqueness bonus. The greater the Wonder to the number of cities ratio, the more unique your empire is. This will inturn give you massive bonuses to growth, productivity, commerce, diplomatic relationships, etc. Greater xp for units built (higher morale). Increased trade and increased number of trade routes. Faster wonder construction for cities that already have wonders. Automatic Open Borders with all civs (for better or for worse). Population boom. Etc. All of these bonuses diminish or disapear as the Wonder to number of cities ratio gets smaller. A large empire will never be able to get these bonuses.
*a small empire that proves its leadership skills will be entrusted with another leaders decision making so that you will control their empire. Make decisions that result in your gain and their loss and you will loose that priviledge. The smaller the power rating over your entrusted leader, the better. If you start to grow in power faster than they do, then it signifies that you are getting more out of the deal (by taking tech and not sharing it, similar with gold and resources, etc). This can happen to multiple leaders so that it effectively creates a massive diplomatic empire that can fall apart if the power that is given to you is abused. The smaller your empire here, the better. A large empire will not be able to achieve this.
*have other bonuses that can ONLY be gained by being small. Expand and those bonuses diminish or disapear all together.