I'd like a proper free for all with 'heats' of a few players each advancing along a bracket, rather than just everyone fighting at the same time. Or, if everyone's fighting at once make it something fun like hide and seek or a maze map or something instead of arena. Cavalry tournaments would also be really fun, or counterstrike ranged tournaments. Just events in general, straight up tournaments are nice but they're a little dry. Organize a fight club boxing event, cRPG's top weaboo tourny, anything.
Another option could be have it based off of "points". In the FFA when you get a kill, you get one point. End of the first round everyone with less than X points is eliminated while the rest move on to the next round. Final round is when there is only 5 people left and winner of that wins overall(last man standing).
Or just have like 5 rounds and whoever gets the most points in those five rounds wins overall.
I.E. Player A gets 3 points the first round, 0 points the 2nd, 5 points the 3rd, 1 point the 4th, and 2 points the 5th for a total of 11 points.
Player B gets 1 point the first, 8 points the 2nd, 0 the 3rd, 0 the 4th, and then 3 the 5th for a total of 12 points.
Player B would win the tourney in this scenario