I am an expansionist in 4x games myself but I'd like to see expansion be a strategy, not the only strategy. Currently the only deterrent to expanding is that population growth is split between your cities. Even then you don't lose growth, just spread it around. This inconvenience is minor compared to the benefits of reckless expansion. Overall growth actually improves through growth methods at extra cities such as the growth enchantments and more food buildings. The bottom line is that currently every extra city gives extra automatic research, cash, production, and opportunities to add more buildings without any penalty. The more one expands the more powerful one is, with no balancing deterrents.
Here are some ideas for limiting unrestrained city expansion while leaving it as a viable strategy:
A ) Take away the "free research incentive." Each city currently provides one free research as soon as it becomes a village. Someone with two cities has double the base research as someone with one city without building any structures in either city. Ten cities means ten free research.
Step 1) Give the capital one automatic research and all other cities get NO automatic research.
Step 2) Make studies provide two research instead of one.
This allows your starting city to be at one research just as it is now. The incentive to add more cities just for the automatic bonuses is taken away but you can still eventually end up with as much research in each city through constructing buildings. You can even end up slightly ahead by making a study in your capital but you've had to invest in building up your current cities, not just spammed more city sites. If this idea was considered too restrictive "free research" could instead be blocked from contributing in cities that weren't connected to the captial. Distant places can't contribute to the cause if they have no way of collaberating with the captial can they?
NOTE: The same procedure for doing away with "free research" could be used for any other free aspect new cities provide such as cash. Example, non capital cities could start out providing no free cash but the starting merchant building could add three instead of two, etc.
B ) Beauracracy is a beast. After a certain number of total cities, let's say four, the penalty for not being connected to your capital is doubled (-30 to unrest instead of -15).
This allows growth beyond a small kingdom size without penalty if it is structured...ie...cities are properly connected. It also allows the reckless expansionist to still do his thing but with an immediate penalty. A penalty that could later be wiped away as they become more organized and connect their cities.
Variations on this idea:
1) The total number of cities before the unconnected unrest hike could be adjusted higher or lower than four
2) There could be an unrest increase every multiple of four cities...-30 at four towns, -45 at eight cities, etc.
3) The unrest penalty could be based on how many unconnected cities you have...first unconnected city is -15, second is -25, third -35, etc. for all unconnected cities. Lack of connection to the capital by so many cities brings about chaos.
4) Unrest could rise everywhere based on total number of cities owned...one city equals no penalty, each extra city adds 2% to unrest everywhere.
The purpose of this thread isn't to debate whether people like expansionism or not. It's to modify expansionism into one possible strategy rather than virtually the only strategy due to it's overwheleming benefits.
These are just broad ideas. Details would need to be ironed out. If Brad and company want to make some adjustments to current expansionism maybe these ideas could be a starting place.