While watching @Smackd and @Ahmash brid I got good ideas about things that would keep pking more active and more fun.
My suggestion is that everytime you recieve another 1k kills you should be rewarded with a pking box. Every pking box should contain random pking items from Mazchna, like ags, serp, barrow itemss, Claws etc. You should get like a bulk (15-25 items) from the pk box and the items would be random.
Problems with this type of suggestion is that people would be farming more.
Another suggestion is to add different skulls above your head and not only the red one. Like when you get 25 ks you get a red skull and when you get 75 ks you get blue one etc.
What do you guys think?