Stacks up to 100 times, 72 hour (3 day) duration.
Upon 10 stacks, killing a player who doesn't award Honor grants you a Bounty Commendation. Use Bounty Commendations to purchase a tabard representing that you're a Wanted person.
Killing any player with the Wanted debuff grants you a Bounty Hunter Commendation.
Use Bounty Hunter Commendations to purchase a tabard representing that you don't tolerate gankers.
Anyone with the Wanted debuff can be tracked from any Hero's Call board on the world map, and a daily quest can be implemented to kill 1 player with the Wanted debuff.
tl;dr: Fight fire with fire, fight ganking with ganking and Bounty Hunters.
EDIT: After re-reading this, this seems more like a new game mechanic rather than fixing ganking. Oh well, cheers.