Valor and Comm requirement can only be tied to mission's rewards, and those cannot be tied to player killing. Else we just get kill trading all again.
A reward/risk system should be put in as well. The masses will not PvP if there is no reward and without risk it almost makes it pointless. Make World PvP deaths damage gear or endurance until repaired. Also a leader board so people can see who the biggest PvP'ers are, World PvP ranks/titles. these little things can encourage people to join the action.
This part is interesting.