Given that a sovereign doesn't necessarily have the money or resources to city spam and that this is considered an undesirable option to force city spam in order to access resources I propose an alternative to the current system which solves the large dark areas within your borders and the inability to access many resources that are out of range.
With watchtowers they can be modified to NOT cost the city any tiles and that you can build as many of them as you like as long as you have the resources and time to build. This cleans up the problem of not being able to see within your own borders and if you build watchtowers on the edge of your cultural borders that can give you better visibility. It would also be interesting to be able to build a watchtower system/smoke signal/mirror/pony express communication system that would become available later in the game for lets say a tile in one city that would cost a lot of resources but would subtract the resources spent on all the individual watchtowers. Basically it would tie your spy and data network together and would illuminate all territory within your cultural borders. Or you could have it automatically happen upon the building of the fifth watchtower which would trigger the network as an alternative.
As far as resources go any city can build on any resource as long as the resource is contiguous with the city via the cultural borders. The city would then build as normal and pay normal cost and gain the benefits of the resource. For example a gold mine on the other side of a gulf could if within the borders be built by city A and the city would gain the benefits even though it might be 20 squares away and another city might be closer. Think how the italian city states in the early renaissance controlled farflung resources.
As a consequence there is less of a need to build cities for no reason other than to gain a resource. You might even pop a city down near a resource just to get the border expanded with the intention of another city using the resource. You might be required to build a road to the location or a caravan.
Seems the game always crashes at five cities with an out of memory error so it would be nice to implement soon:)
