The edge points for PK creative an incentive to behave in a way you don't agree with. I happen to agree with you, despite my ability to farm those points. However, I would like to suggest that now is an excellent time to consider adding incentives for behavior you do want to see.

For example:

Send and receive 1000 tells with other PC's, max 50 per PC. (Tells are RP, and spamming doesn't get you very far and will get you ignored/ROTD'd)

Gain a rank in a group of 2.
Gain a rank in a group of 3.

Same but with 10 ranks or something. Possibly per-level ranges. i.e. Gain 5 ranks in a group of 2 or more pre-level 10. Ranking together is playing with others = RP, even if not a ton.

Complete a quest with another player*

Engage in battle with 10? unique PCs.

Gather X explore points while in a group of 2+, 3+, etc.


* Most quests are not group friendly, but it seems like it wouldn't require a ton of work to make them such. If you are asked to kill 100 zombies, shouldn't kills for your group count? You recruited others to aid you... all of you should get credit instead of just the one that did the most damage (or however that gets calc'd now)