Harbors
Currently you have to build a city on a beach in order to build a harbor (once the tech is researched.) Well this kinda poses a problem especially if resources are close to the beach but no close enough to build the harbor and still use the resource without resorting to city spamming or waiting many turns for your ZOC to encompass the other resources. I think the way to solve this would be to either,
1) Treat the beach much like a resource and build a harbor on it once the tech is built and it is in your ZOC. This way the city does not have to be on the beach.
2) Once the tech is research have a Harbor kit much like the Pioneer kit to be put on a unit and sent to the beach to build a harbor. You could also use this same concept for Fort building with of coarse the appropriate tech researched for that.
What do you think? I perfer option 2 myself.