One of the tech research allows you to move with less energy on enemy’s territory. Apart from trolling, there was very little strategic need for this. Most of the time, you just destroy towers one by one. Considering the tech was only available much later into the event, this was kind of useless.
One way this could make it interesting, and also adds more reward to the event, is to give all alliances a flag that is located on a tile near hq. If the alliance gets to maintain that flag, all players in that alliance gets 1 pro chest. However, enemy is able to go on top of that tile to steal the flag. If the enemy takes that flag back to his hq, his alliance gets the pro chest, i.e the first alliance gets 0 pro chest while the second gets 2 (1 from stealing the flag and 1 from maintaining his own).
This adds another layer to the underdog too. Imagine if there are two strong alliances fighting, say, for the center, and the underdog knows they can’t win already, they scout properly to see when those stronger two alliances are having big battles, then at the same time, snuck into two of their bases and steal their flags. The underdog may not win the war but they may have just gotten their entire alliances at least 3 pro chests by the end of the event.