I think it would be a cool and interactive community game for players on the server if there was a fun pk system implemented.
i've seen it done, it would go something like this.
an announcement would go out for players to enter the fun pk waiting room, it would tell you what kind of tournament it was and what the prize for winning it was. ( blood money, awesome weapon, or amour)
Main pking: everyone in the waiting room would be set to max stats and get a choice of weapons and amour to pk with
Pure pking, berserker: etc etc different stats and weapons for each build.
everyone would enter a 1v1 match with all players that entered the tournament, they'd duke it out round by round until the final 2 battled for the prize, single elimination.
players fight beside each other in their different squares.
( picture from the OSRS deadman mode final)