This is my older post (http://boards.lineage2.com/showthread.php?t=226757), it explain well why new pk system is one big bug, in fact.
But few more words about. Now only way to clean pk is to use fame points. To clean one pk you need 500 000 fame points. From one castle siege you take around 25 000. So you need 20 sieges to clean 1 pk. Or you need 40 weeks, almost year for 1 pk. Even if we put forts in formula, the result will be ridiculous.
NCSOFT could just ban pk, instead this. It's the same, but now players are deluded that there is still pk in server. Don't pk! There is no such a think like pk/reputation system. You can clean karma. I've cleaned tens of thounsends of karma. But you can't clean pk. SYSTEM DOESN'T WORK.
And without pk game becomes very imbalanced, you can read why at the link above.