I have 2 alternative rule sets for your perusal.
1. "2vs2vs2 aka Team Building Exorcise"
All players are bound in a self arranged pair, live or die both players win or lose together as equals. No holds bared.
2. "Hide Your Shame" all players must demand any player who has a visible legion after turn 20. Strategic deception and all your legions being dead the only reprieves, additionally being excommunicated frees you from those responsibilities but not anyone else. (note:even if you WANT to excom yourself you must still maintain demanding until you are expelled from the concave and unable to demand, which might mean you don't have enough slots free to excom).
You must target valid demandees in a clockwise fashion (the next one along first), expect lots of praetor battles and a shortage of order slots.