There should be a permanent threat, but I'll start this post with one thought:
When a fief within your kingdom/faction/clan gets sieged, you have the option to teleport into the battle when it starts, so that you can enjoy more siege defenses. You wouldn't get to bring your army, and you either play as your character alone or take over an existing character. This would allow players to have the fun of a siege defense, while having minimum impact on the war. You could extend this to offensive sieges as well. Afterwards you go back to what you we're doing.
When a fief within your kingdom/faction/clan gets sieged, you have the option to teleport into the battle when it starts, so that you can enjoy more siege defenses. You wouldn't get to bring your army, and you either play as your character alone or take over an existing character. This would allow players to have the fun of a siege defense, while having minimum impact on the war. You could extend this to offensive sieges as well. Afterwards you go back to what you we're doing.
