And the second is a game concept one - going wide should have pros and cons, but right now the only con is psychological one, if you disregard speedbumps. There's no real action>consequence dualism from the choice of going tall or wide - wide is "tall +" right now.
My point was, that until Civ 5 there was no gamestyle choice between Tall and Wide, the concept didn't really exist. There was only the pace of expansion, how fast you expanded was your consideration, not whether you expand or not.
We basically created this concept of "Tall" and then decided it had to be balanced.
To show an analogy, a player might argue "I want to play Civ 5 but with almost no science". Currently that playstyle is not supported in the game. Now sure you can play games with differing amount of science, but if you play with no science you are pretty much going to lose. So do we now need to balance the game around a no science playstyle? I would argue we don't.
But I don't want to argue too much, I do want to keep this constructive, so here are a few more thoughts:
Firstly, I am working the problem with the idea of "slowing" expansion, not of "stopping it". Bottom line is, if you want a 3 city empire to be equal to a 10 city one, then the 3 city empire has to get something that the 10 city empire DOES NOT get, or that you apply such a strong hammer to bigger empires that you begin to make expansion not fun.
To me, true equivalency can only be reached through victory conditions. Tall and Wide cannot compete in the same arenas, they need to compete in different ones.
So how do we slow the incentive for expansion?
When I add a Civ to my empire, I actually lose quite a bit:
1) The culture output for my entire civ is reduced by 10% (from a social policy standpoint).
2) The science output for my entire civ is reduced by 5%.
3) -3 Happiness
4) Cost of the settler (whether is money or the lost growth/hammers).
5) Increased difficulty to make national wonders.
In return, I gain the following:
1) An immediate increase in tiles of control.
2) +2 food/+1 (+2 on a hill) hammers. Effectively a "free population".
3) Access to potential strategic/luxury resources.
4) Ability to make multiple copies of the same building.
5) Potentially faster growth (Two Size 3 cities require 78 food, one Size 6 city requires 171 food).
I'm ignoring all of the benefits around policies and faith for now, lets just start with the core mechanics. Lets just take a quick look at some ideas around these core concepts:
First lets attack the costs:
1) Increase the Culture and Science penalty for expanding. A commonly discussed idea, and not my favorite. I really really really hate this "hammer" approach to expansion, and would prefer to leave this alone.
2) Adjust the -3 happiness for a new city. Also one commonly adjusted. An easy change, it won't fix any problems but its a way to polish the numbers.
3) Change the settler to be food only for production. The idea here is to create a bigger hit to the growth bottom line. Right now, I can build a settler out of a high hammer city (and I usually do) and effectively create population out of hammers. By making settlers require food, it is still food = population. That combined with the loss of growth while a settler is in production means the free population for a new city is a little less free.
Of course we can also consider the old idea of just removing a population from a city when a settler is produced there. Its been used in Civ before, and in many other 4x games.
Now a few ideas around the benefits:
1) Adjust the base yield of the city. This one has also been used frequently. What inevitably happens is you have trouble balancing the need to give a new city enough resource to get off the ground while not giving it so much that Wide becomes automatic. My recommendation is to leave the base yield alone and focus on other areas.
2) Adjust the luxury resource benefit. Already proposed, I think its a good idea. Wide gains more luxuries, but Tall could gain more benefit from them.
3) Adjust buildings to be a stronger %yield, and a weaker base (+X yield). Basically you reduce the benefit of multiple copies of the same building. Done many times, its polish would have to occur when buildings are discussed.
4)
Adjust the growth mechanics so that higher populations require less food.
I haven't seen this one discussed much so I'm going to focus on it.
If you strip other considerations and just look at the core, small cities grow faster than large ones unless large cities focus on extra food. That right there may actually be the primary reason that wide cities are better. Its not that Wide cities get more happiness (because as has been pointed out, extra happiness is not that big an advantage right now). It is because Wide cities can use them! They simply have more people, so they gain more stuff.
If the growth mechanic was changed to limit this effect, than a few large cities could obtain a similar population to several small ones. Wide civs would still have the ability to control happiness better (which I think makes sense, it mirrors the "overcrowding" idea of megacities) but it lets Tall compete on a pure population game.
per city.
output per 
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output per 
I guess what I'm trying to say is don't forget were all here to have fun. 
instead of 
, stops growth during production and resets the birth count towards a new 
