Because it's a side show, not the point of the game. It's not, nor should it ever be, the main focus. They could have gotten rid of all pvp rewards and just had pvp in the open world for when you run across an opposing faction while doing PvE and it would have been fine. As is they've already thrown a bone to the PvP community with even having wz's, pvp gear and such.
Yes, I love pvp, yes I pvp often, no I don't think it needs rewards or alot of focus in this genre of game.