World PVP will never be a even playing field though, at any time it can be 10 vs 1 etc etc, the only way to make it even is by having a system that puts the same amount of people in the area, but now it is not world pvp anymore. I don't think you can reward anyone for this as world pvp will never ever be even, that is why it is world pvp.
I can see adding gear for killing say a city leader once a week to be a nice bonus for doing it and maybe this will introduce more pvp, but it all depends on where people will be idling in the next expansion lol You can give out all the rewards you want, but I don't think it will encourage more pvp, people will be just like oh look they are killing our boss, dude its ok they respawn again etc