If you want to have a lot of people or factions in your event it might need more planing with the faction leaders.
The way you did this event there was little to no preparation time and I don't know how well your communication with the other leaders is but they have to get their members notified and maybe check if the event is even appropriate for their group.
Other than that it is nice to see that people still desire RP events instead of the usual pew for no reason.