Add a setting where should a player be booted, all their territories are given "x" armies and will become neutral. Would help games remain balanced. Could perhaps also have it be if a player is booted within "x" turns.

Additionally, this could be done for surrenders.

This would allow diplo games to remain balanced even when players quit or are booted.

You could just use the advanced diplo mod to have a pacified AI take a booted players place.