There are arguably many more reasons for implementing this feature in a simple *right click target, opponent accepts* manner. One of the greatest things about duels is they could be done virtually anywhere, at any point of boredom. Two people didn't have to agree they wanted to duel, teleport to the nearest city, sign waivers in triplicate, and then turn them into the Vice Duel Chancellor before stepping into the arena for likely a 30 second duel. It was a right click and two button presses. Dueling is a great way to coax players into a deeper understanding of their class mechanics. It would be lucrative, and not detrimental to the overall flow of FF14: ARR, to add this mechanic to the game.

Thanks for your time,

Sincerely,
A bored warrior in Gridania