Anet has the answer to their existential dilemma. They built it into the game. It’s the last WvWv …. W.
From a chivalric standpoint, neighbors wouldn’t let their neighbors get shellacked by some large imperial force. There should be a vote option that’s hidden from all others knowledge. You can either vote Truce or War with an opposing faction. Once enough votes are in favor of either Truce or War those players are no longer worth WXP. You can still kill them and their buildings are worth XP but you receive no XP up player death.
The diplomatic relations could be placed into the UI and you could see what factions you are at War with or have a Truce with. They could change throughout the day or week depending on what things play out on the battlefield.
The killings still in the game
but maybe commanders from opposing factions could unite and start making things more difficult for these stacked servers.
More thought should be put into diplomacy. I am surprised it’s so taboo on the chat.