I found this quote from the Letter from the Producer at E3 2014.

Are there any plans to add 1v1 dueling?
As for actual in-game content, we aren’t sure we will as we don’t know if we can add it into the system and then make fun content. We do understand that players want to use Dueling as a test for looking at dps, damage, armour, etc, and this is something we would like to do.