A new mod called "Player Manager" has just been released.
This Mod can eliminate entire players, erase their armies, swap them, or have one player absorb another player's territories. All these features can be voted into effect by the players. Once a vote threshold has been reached, the voted action processes.
This is designed to be used against toxic players, such as rule breakers in diplomacy games.
Note that you should only use this mod with players you trust, as it could be used to eliminate anyone if the rest of the players vote to.
When included in a game, go to Game > Mod: Player Manager to use it.