This very possibly could have been suggested by now, I haven't seen it yet hovering around the message boards for a while (I don't post much) so just in case this hasn't been suggested here goes:
Personally I'd like to see city production divided up on more than one task at a time, you'd be directing a percentage of your city production to various tasks every turn (building workers, attack units and constructing a building, etc). This is pretty straight forward and has probably been suggested, I came up with this however thinking about something that may not have been. Simply put, large ships should never be built exclusively in one city. You'd have the guns of your battleship for instance being built in Rome for example while you'd have the Naval quarters built in Neapolis, and the hull in Veii, etc. This to mimick specialization of building parts, maybe as cities build many units of one type they begin to be specialists in steel work for example so one city's Hull would be stronger than the hull built in a city that was not a specialist in steel work. Tanks and smaller units of course would be produced in one city, soldiers would be trained in one city although perhaps you could train a standard soldier in specialized methods only by sending them to cities that specialized in that type of fighting (in the earlier ages anyway, modern cities should have all types of combat training expertise).
Basically my suggestion is to treat large sea vessels more like the Space Ship of CIV2 and 3. Most importantly however, is the breaking up of production on more than one task!
One last suggestion, ships should take up more than 1 square where your attack could be directed at the rear portion or front portion of any ship with different defense statistics depending on where you attack the enemy ship.
Just my 2 cents.
Personally I'd like to see city production divided up on more than one task at a time, you'd be directing a percentage of your city production to various tasks every turn (building workers, attack units and constructing a building, etc). This is pretty straight forward and has probably been suggested, I came up with this however thinking about something that may not have been. Simply put, large ships should never be built exclusively in one city. You'd have the guns of your battleship for instance being built in Rome for example while you'd have the Naval quarters built in Neapolis, and the hull in Veii, etc. This to mimick specialization of building parts, maybe as cities build many units of one type they begin to be specialists in steel work for example so one city's Hull would be stronger than the hull built in a city that was not a specialist in steel work. Tanks and smaller units of course would be produced in one city, soldiers would be trained in one city although perhaps you could train a standard soldier in specialized methods only by sending them to cities that specialized in that type of fighting (in the earlier ages anyway, modern cities should have all types of combat training expertise).
Basically my suggestion is to treat large sea vessels more like the Space Ship of CIV2 and 3. Most importantly however, is the breaking up of production on more than one task!
One last suggestion, ships should take up more than 1 square where your attack could be directed at the rear portion or front portion of any ship with different defense statistics depending on where you attack the enemy ship.
Just my 2 cents.