I use to believe there was a right build for each class and the right gear, the right way to distribute your stats etc... until I found out there is no better class, no way to correctly distribute your skills, there are wrong ways to distribute your skills though.
It all depends on the way you play. I duel all the time, non-stop in 2 worlds so a dueler is a better fit for me so I can keep my motivation up. If I dueled moderately then a soldier would be better for me. If I was only defensive then a soldier would again be better.
There is no better class and no best dueling gear. It all depends on how you play and how you distribute your stats. I would never be a soldier, if I'm going to duel on a world I want to duel all the time, if I didn't then that's when I pick an adventurer or a worker.
There is no better class.