This feature is outrageous. How should smaller struggling kingdoms fight with stronger once? And applying it retrospectively will just destroy weaker once. On our server we already have one bully who is hardly ever matched. With this feature he will just crush everybody with no need of going outside his castle. Utterly stupid!
I think the biggest problem is not that you can be destroyed, because it can always happened. Whale will come to your town and kill without loos. Problem start when you are healing in capital, then weaker players can revenge you for 7 days, day and night and you cant heal, build and gather resaurces. Its game over for you. You can use shield only 8h and i think its not possible for example to collect 180k wood for castle upgreade in that time.