The current combat system has no benefits for attackers if the defender is under cap. Same goes for the defender. An honor/glory "resource" should be implemented into the game. When you lose your h/g decreases. When you win your h/g increases. There could be a store that trades h/g for various items or they can be used for ranks that give permanent boosts or boosts that are only active when you have the amount of h/g for the rank.
(Coninuted)(more ideas) The amount of h/g gained/lost should be calculated by either number of troops or the attack/defense power or just by the TH level. There can also be research to increase gain or even decrease losses. The new legendary dragons can have a passive that increase h/g gained too.