So you mean like galciv where if you build anything before the population reaches a certain level the upkeep costs you more than the taxing of the people generates?
I haven't played GalCiv. It might be similar. I'm thinking along the lines that new cities incur cost (
drains the empires treasury). Eventually, as a cities population is increased, the tax income will break even with the costs (
no drain on the treasury). Some time later the city actually begins returning a net profit (
puts money into the treasury). So if you have too many new cities you will go broke and your civ will collapse. The purpose being to naturally compel players to wait for old cities to mature before building new ones.
I whole heartedly agree with the OP. Granted my personel taste is to build one mega city before I even think about a second. I love the idea that in the long run someone who has expanded will actually reap the rewards from having many cities yet thats fine if they had to think carefully to get to that point and they actually incurred a cost and had to maintain a considered balance to do so.
I tend towards moderate early expansion. But I like to mix things up to either side of that mark. Ideally I'd like my 4x TBS to provide viable options for an OCC (One City Challenge) all the way to a full blown ICS (Infinite City Sprawl). I don't want a guarantee of victory just for cranking out mass cities. And I don't want to be overwhelmingly under-dogged just because I've chosen to go city light but infrastructure heavy.
What I seek is the challenge of juggling economy against expansion, infrastructure, military and technology. I want choices and I want opportunity for creative solution making. I think it should be difficult to manage a large empire. There should be risks and heavy costs. So there should also be an eventual reward for doing it successfully. But the civ which is investing heavy in expansion, should naturally be falling behind the civs who are taking a more balanced approach. By default, Victory should favor the balanced approach. The trick in expansion heavy strats should be to manage it such that you don't fall hopelessly behind. There should be significant risk of becoming fatally out-teched, out-funded and under-armed in relation to everyone else. If you manage it well, then eventually your investments will begin gradually paying off. It's up to the player to make it happen before it's too late. And then, after catching up, the player must be able to successfully capitalize on it to gain an eventual lead.
One thing I failed to mention in the OP: I'd think that this method also entails a decreased unit and building production rate. This would represent empire wide logistics becoming strained with the burden of fledgling cities. It's purpose would be limit the effect that rapid expansion has on ones ability to produce buildings and units. An increased Gildar cost for new cities can portray logistic strain while bleeding the treasury. But it seems that we'd also have to limit production capacity. So I wonder how tough it would be to incorporate a construction penalty for new cities... but only after a threshold of N city size X has been reached? ie: After three level 1 cities, the next level 1 city experiences decreased production. Or all level 1 cities have decreased production. [And perhaps have an expensive city size 5 building which increases the N threshold (teched for late game)?] Wouldn't want to limit production for the smaller civs going the balanced route. Just for the civs going hyper-expansive. The city level 3 limit for armies is helpful towards reducing the edge that three level 1 outposts would have against one level 3 city. But as things are now, the ICS'rs still have an edge I wonder.
*I'm sure from a design and development standpoint, this is all much easier said than done. But the point is to make a great game, and for that I think a game needs breadth in order to appeal to a wide array of player style. So I think these things are worth brainstorming.