In reality, air strikes without invasion are a way to punish a far away nation without risking much. Of course only if the other nation is weaker and cannot retaliate properly. In civ4, on larger maps, there is very little point in wars with nations that are not your direct neighbours - at least before the modern age and airplanes. You can't even bomb their harbours with frigates. IMO we need more ways to weaken civs without full scale invasion, not less. Espionage is gone already (not that it was powerful in Civ4). Ships being able to do harm to coastal cities is a good move. Air strikes that can weaken an enemy economically should be in. Commando missions should be in.