Why do topics about Duels always fall into debates about balance... Who cares about balance with Duels?

If it was something in the Wolves' Den you queue into, with rewards to boot, then I'd have an issue there. Just make it so it's same verses same then, that way it is purely about your individual skill as, say, a Dragoon, verses another. Short duration with a time out being a draw.

If it was open world (like it should be), then there is no issue. Provided measures are taken to not make it too intrusive on PvE players (slapping sending and accepting Duels behind a PvP Rank requirement should deal with griefers). We can balance it ourselves that way. That lets us do a whole heap of good things; Something to do while waiting on queues. Practicing without it affecting the real match. Teaching others, either by showing them a Duel or Sparing with them. And yes, challenging the odd person seriously.