Alright guys, this is pretty obvious but since it is my opinion that in EWOM, it doesn't work, maybe it's better to spell it out.
City development takes time and resources, therefore the player needs special moments to look forward to.
The very first one is the creation of a structure that allows to research technologies.The tech menu opens: WOW!
That comes very soon (hopefully) so what's next?
After a few turns players may be able to also get a spell research facility (spell book opens, WOW again!) and a after that a building that allow them to get materials. (finally we can build pioneers!).
- A moment that is missing IMO is when the merchant shop is opened and weapons can be bought, that could also be a bunch of different stores one for each kind of objects: weapons, armors, magic items and, why not, clothes (the game has a great clothing system but units never change during the game) -
Also a port could be an interesting thing to create, if it finally becomes useful.
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Anyway, After those things are built (which is relatively soon) IMO a city is pretty much developed and the only interesting moment after that is when a city grows and a bonus can be chosen. unfortunately growing doesn't allow to get very interesting building option, and from that point on the game is mostly about building pioneers and make more level 1 cities.
IMO when a city reaches level 2 it should be much more specialized than it is now. If it is a port city everything else should become secondary and even a blacksmith and the magic shop should specialize in maritime items. Cities should also be able to get food from the sea (maybe by building a fishing boat fleet) and so on.
Other directions a city development should take could be: agricultural (food), economic capital (banks) or maybe a castle (like in medieval total war, where a city developed into a castle becomes very hard to conquer but produces no taxes, being a military structure).
As it is in EWOM a small bonus in one area is not enough to give uniqueness to a city. I believe a completely different range of building and bonuses should open according to that choice. (further choices should either improve those buildings or allow to become an hybrid between two kinds of cities).
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LIMITING CITY SPAWNING:
IMO limiting pioneer spawning can simply be done by understanding that "a pioneer" is in fact a large portion of the community migrating (like in most games of this kind, like Masters of Orion II for example). That way taxes are the same, since tax payers are the same number (just divided between two cities), the product of the fishing community in a port city should be less when there is less population and so on... Notice that in MOOII a planet cannot have more than a certain number of people according to its size and earthlike quality, so after that number migrating becomes quite necessary. The concept should be the same here: a city buit around an agricultural area should be able to reach a large number of inhabitants, one built next to a mine less... and migrating should become necessary at some point but useless too soon (unless a very special resource has been discovered).