Thematically. If a territory is assaulted by demons and the people you pay your taxes to aren’t defending it well, resulting in damage to your town, you wouldn’t be very supportive of that group of people. At the same time, if your enemy nation is attacked by demons, while they are shifting through the rubble, is the perfect time to attack and take over.
So I suggest making it so a failed invasion defense will automatically throw the territory into a state of conflict, letting people declare war on a first come first served basis without having to grind influence.
I think this is a good idea for the game because:
-it would make invasions more important content. invasions feel like gate content, keeping people constantly rebuilding and just being annoying in general. ive seen some companies not even bothering to defend because they just don’t care. But if your territory could get declared on failure, it becomes a much bigger thing. Something guilds would take much more seriously. It would have a bigger purpose than making everyone rebuild. It could have big impacts.
-it would help shift the balance of the game. More wars would be declared leading to more potential territory shifts. Combined this with something like 1 war per day as other people have suggested, it could really shake the map up and breathe fresh life into the game.
-it would help the importance of anti-corruption armor and gear, in turn increasing the cost of those items on the market and providing another different source of income to crafters and dungeon raiders. We are already seeing this with anti-angry earth and anti-ancient equipment in mutations. As the majority of people approach end game, the items that sell on the markets become more limited, so anything that can be increased in value is welcome in my opinion.
-It would be thematic and awesome and increase the immersion of the world.