I believe the addition of a quest system would greatly benefit the server and get players hooked on the game mode.
This Interactive quest system would consist of fun fetch quests, exploration quests, and kill quotas .
For example a quest could be collect 20 lobsters, kill 10 players with a machete, steal a helicopter, visit the floating island, etc.. rewards for the quest could be XP or money or guns maybe even a special small perk that is unique to a hard mission.
The addition of this Quest system would break up the monotony of grind kill and shooting.
Starter quests could be very basic and essentially be tutorials to get new players into the game mode by getting them to explore the mechanics of the game.