So far dueling as been a very fun addition and on its first day (at least on my server) the arena was full of people trying it out, talking, sharing tips, etc. Haven't seen any BM yet, let's keep it that way!
The following is a list of things that could use adjustment to make the experience even better, starting with the obvious:
Item Level Sync
We all want it, let's have it. It has been the standard since late Wolves' Den to equalize item levels for skill-based gameplay.
Cooldown Reset
Fluid transition between duels would be a huge quality-of-life improvement, especially for jobs with long cooldowns.
Cooldowns and the duel counter
It seems everyone would greatly appreciate being able to turn on stances at the beginning of the countdown, possibly even letting stances stay on (includes Aetherflow).
Melee Range Adjustment
Player melee range, in PvP areas, was increased to deal with the server's net code in chasing down opponents. Currently in the Wolves' Den Pier, it remains as the PvE range which can cause some issues unless your character is borderline inside the opponent (the inconsistency is what is most troubling). Please look into restoring the PvP range within the Wolves' Den Pier.
Potential others?
If the ranges weren't adjusted, it's highly possible that other things may have been overlooked, such as damage calculations. I can't be sure of that, but SquareEnix might via its coding.
Kindly discuss and add your observations and what you'd feel would add to enhancing the experience.