I believe revamping the map cycle so that city maps and country maps are alternated (without necessarily killing the randomness) should solve the issues raised. Also, it helps to ensure that no map is repeated unless every other map is played once.
Introducing voting would more or less result in the server having essentially 2 to 3 favourite maps played all the time as I don't see how the majority would favour country maps. Also, player count drops for the most part when country maps appear consecutively, not when a country map is played after a city map.
I agree that FC and RC could use some renovation (faster vehicles, a ramp from FC terrorist spawn to road perhaps?).