Any fighter manages, in GbG, to cross a defense with 2 waves of at least the double defensive bonus than his offensive bonus.
On average, players have 2-3 times more% attack than defense.
In view of these observations, it is futile to try to defend your city, especially since if you harvest on time, you have nothing to gain.
For% defenses to become attractive, it would require a major overhaul of the defense system.
By multiplying the defense values by 5, the fighting would already be more balanced and would offer a real choice in the management of his city.