1) OK, I confess first up that the 2N+2 was just a number I plucked out of the air. The actual number would depend on Gameplay balance issues.
2) The base maintainance cost of ALL cities would be boosted by a flat rate-i.e. if a city cost 10gpt to maintain, but resource shortages had boosted maintainence costs by 10%, then this city would now set you back 11gpt.
3) Resources would-as always-grant economic, health and happiness bonuses to the city in who's radius it is-that would remain unchanged.
4) Too easy, the size of a resource deposit would depend on the number of that resource on the tile. For instance, a size 4 coal deposit would consist of 4 lumps of coal. A size 3 horse resource will consist of 3 horses.
5) When you trade a resource, you will select the number of 'Units' you are trading. So, if you select your size 4 coal deposit, you will enter a number from 1-4 to indicate how many units you are offering.
Now, the key issues are (a) different deposits of the same resource will appear in your trade screen as a single icon with the
collective size next to it. If you click on the icon, it will show you a breakdown of all the different deposits.
(b) Your collective resource size determines the total number of cities you can build, not the size of individual deposits.
(c) Exceeding your resource limits has a few key effects. (i) The increased maintainance costs for cities; (ii) increased build times for units and improvements; (iii) an increasing chance of the resource becoming depleted.
If a resource becomes depleted, its size gets halved-rounded down. This means a size 1 resource disappears, a size 2-3 resource becomes a size 1, and a size 4-5 resource becomes a size 2.
The important thing about this model is that it drives both trade and warfare much more strongly. After all, just because you have a single deposit of coal, does not mean that you won't need more. If it is a size 3 coal deposit, then in my system it will only support 8 cities before the efficiency of your cities starts to drop off. So now you will need to seek out more to keep your economy running efficiently. Building terrain and city improvements-as well as researching techs-can either increase or decrease the equation for determining city limits.
Anyway, hope that makes sense.
Yours,
Aussie_Lurker.