A big problem is.. the zerg comes and save the keep. They use their supply often not enough (some dont care) to repair all. Someone run back and repairs the rest. But they dont want to run back and forth 10 times. So things dont get repaired.
Defence tactics cant be used, when U cant get enough supply to close wall/gate after the attacking enemy r inside. .When closing gate/wall u often can defend the keep with half of the attackers.
Have just checked all "our" towers/keep etc. none of them r 100%. and then I dont want to waste seige on them.