I feel that this post was born out of the fact that some players would like to do a PvP DQ if the reward is sweet enough, yet have no targets.
A simple change to the PvP DQ could solve that.
Give the player a 2nd choice...reward remains the same
Defeat x active players in normal PvP or Defeat xxx creatures.
No other task is needed, it is either defeat players or defeat creatures
Once a click is made they are stuck with the choice.
Maybe this would entice pvpers to go kill some creatures for change
Another idea swimming in my head is having a lawless level, say every 1000 levels.
After next new content that would make 5 areas.
In those areas your pvp range increases to +/- 500 or even 1000.
you can invite some friends in there to wail on for your DQ or (pvpers would love this)
Hang out in the area waiting for a unsuspecting leveler passing thru!