Junky makes some logical points about the inefficiencies of breaking a walnut with a 50 lb hammer.. However, he fails, by making the assumption that the enemy plays the game using any logic at all. Truth of the matter is, most win the war guys are just flying somewhere to blow stuff up with their comrades. If they get there in bombers and the town is close to down, and there are big juicy hangars up...then they are going to take em out, with lack of better option. Anytime you destroy an enemy target you are helping your country out, right? Well, that's the general line of thought of most players anyways, and you can't blame them, it makes perfect sense from a win the war standpoint.
Let them completely flatten and horde bases. Nobody who takes part in those types of sorties is going to find much, if anything at all to shoot at. Just a bunch of clumsy, starving hyenas fighting over an emaciated wildebeest or two. And to that end, they will find no enjoyment from the game.