Noone will bother to kill that city.
Big loss of time. (with today strat ).
Exept if...big formations of bombers come ( 1 form=10 or more planes ) and again you will need many players. (exept if you replace them with AI).
One city big like this means maps will never change.
Every change of map will be a little Stalingrad with combined operations
of gvs and bombers when at the same time fighters will try to kill them or protect them.
Nice idea and nice plan, IF is this what they want, BUT you need All the players of your country for that city and still maybe they are not enough.
In two words, that city can concetrate the whole war in 1 point gvs fighters and bombers, in a giand battle and furball (nice
BUT if the players dont bother, it will be just.. fubar.