We need to be able to organize our own fights. Dueling is good, but what if we want to do 2v2 or 3v3 fights, or more? Maybe a guild wants to setup their own teams to fight each other for practice. Currently, we cannot do that easily. Players have to go to PVP zones where a fight is likely to get interrupted by other players or NPCs.
Allowing players to host their own team fights would also create an environment for new pvp players to gain some skill before going out into the wild.
Nearly every multi-player game I have played has this sort of feature. Adding player hosted matches to ESO would be a huge step forward.