Stilgar08 said:
My bet is the cap will stay! I believe hereby they want to "encourage you even more to specialize your cities and really think and make a DECISION what to build where...
There are better ways to do that than the hard cap. Perhaps the effectiveness of some National Wonders is related to some attributes of the city. Maybe some National Wonders take up space in the city radius. Maybe some National Wonder's effects propagate according to distance, so you'd want it smack dab in the middle of your civ. Maybe some National Wonders require the presence of some resource in the city radius (like the Iron Works in Civ3).
City specialization should have a compounding effect. Let's say there are two National Wonders that increase science by 50% (150% of the base). Having both should increase your total science by 125% (150% * 150% of the base). If you have 2 cities with 10 science base, building one National Wonder in each city will give you 30 total science (15 + 15), while building both in the same city will give you 33 total science (10 + 22.5). That sounds like a reason to stack all of your National Wonders in a single city, but it's just a reason to stack all your science National Wonders in a single city.
Due to health, it will be easier to get 3 cities to population 10 than to get 1 city to population 25 or 30. Since growth is (presumably) harder to come by, you'd probably be better off with a setup where one city has 3 scientists, another has 3 farmers, and a third has 3 merchants than you would be if you had 3 cities each with a scientist, farmer, and a merchant, due to the limited population growth and the compounding effect of specialization. Maybe the effects of specialists should be multiplicative instead of additive. Rather than a scientist increasing a city's beakers by 2, a single scientist might increase its beakers by 20% (120% of base). Two scientists increase it by 44% (120% * 120% = 144% of base), three scientists by 72%, etc.
Presumably, you won't have all of your cities with equal base science; one city might have a high base science rate (due to the Great Library), while another might have a high base commerce rate (due to being your only port), while a third might have a high diversity of religions (being near the border with 3 other nations).
In fact, it sounds like the National Wonders cap could make it
harder to specialize cities because you might only be able to build two science National Wonders in one city of the available five science National Wonders. That assumes that there's more than two of each National Wonder type, of course, which may be false.
I'd make this even more of an effect by incorporating two of my favorite ideas: education and increased effectiveness of older improvements. For the former, you would have to make an investment into a citizen to turn it into a scientist. This would take time and perhaps money; it wouldn't be like previous Civ games where you could instantly change it. Thus, you would have less flexibility in what you could do. Education would propagate itself, so a University in a city with scientists would become more science-oriented. That University would then train scientists faster and more cheaply than other Universities, etc.
Secondly, the older an improvement is, the more effective it should be (like with culture generation in Civ3). A new Marketplace might boost commerce by 50%, but a Marketplace that has been around for 1000 years might boost it by 75%. Because of the compounding effects described above, you'd be crazy to have scientists in the trade city and merchants in the science city. It would be a huge waste. It would also compel you to choose early on how to allocate your limited resources. It's 1950 BC. Do you build a Marketplace now and then a Library in a particular city or vice versa? Your choice will have long-term ramifications. If you're playing the tech trailer who buys everything, you might choose to build all Marketplaces early on to become a financial juggernaut but a scientific weakling. Or vice versa. It would be a way of simulating the "acquired" leader traits that some civ fans would like (as opposed to the fixed leader traits that we will get).
This is getting ridiculous, just like the discussion about the industrious trait and if wonder is a typo and should be "worker"... 
